Occupying 766 square miles, Oslo Fjord attracts Oslo residents and tourists in droves, especially during the warmer months. Water vistas are available from many parts of the city, including popular attractions like the Oslo Opera House and Akershus Fortress. You can also opt to hit the water in a canoe or kayak, but to get the full experience, consider signing up for an Oslo Fjord cruise. Sightseeing and fishing excursions are available on everything from inflatable boats (known as RIBs) to sailboats and yachts to ferries throughout the year.

Traveler-approved cruise operators include RIB Oslo and Norway Yacht Charter, but the cheapest and most popular way to explore the fjord is via a tour with Båtservice Sightseeing. Affiliated with Norway Yacht Charter, this ferry company offers several fjord tour options, such as a two-hour daytime sightseeing excursion and three-hour crab-, jazz- and blues-themed cruises. Previous visitors suggest booking the evening boat tour, which includes three hours of sailing and a highly regarded all-you-can-eat shrimp buffet. But remember to bring extra money for drinks and a jacket if you plan on sitting outside.

Vigeland Park, which resides in Ullern and Majorstuen's Frogner Park, is the world's largest sculpture park featuring works by a single artist. The park is composed of five main areas: the Main Gate, the Wheel of Life, the Fountain, the Monolith Plateau and the Bridge. Its highlight is its 200-plus bronze, granite and wrought-iron sculptures created by the park's namesake, Gustav Vigeland. People come here to sunbathe, picnic and wander the beautiful grounds.

Travelers love this park's well-maintained grounds and, of course, its world-renowned sculptures. But remember, Vigeland Park is one of Norway's most popular attractions, so it can get crowded at times. To avoid hordes of tourists, consider arriving early in the morning or late at night. Some reviewers suggest timing your visit during summer's midnight sun.

U.S. News Insider Tip: Grab a gelato cone (popular flavors include mango and chocolate) at Paradis Gelateria Karl Johan – it's the perfect treat for walking through the city. – Leilani Osmundson

Karl Johans gate stretches between Oslo's downtown train station and Palace Park, an expansive park that surrounds the Royal Palace. Boutiques, cafes, bars, nightclubs and hotels are just some of the amenities you'll find lining this central thoroughfare. Inside the smaller Studenterlunden Park, which borders the street's western end, you can catch a performance at the late 19th-century National Theatre, go ice skating at the outdoor rink or simply enjoy a leisurely stroll. This section of the boulevard is also a block away from the National Gallery, one of four buildings that comprise the National Museum of Art, Architecture and Design.

U.S. News Insider Tip: Enjoy a delicious meal at Lille Herbern, a waterfront restaurant on an island at the southeastern end of the peninsula. You have to take a short ferry to reach the island and the restaurant is only open in the summer, but it's well worth a visit for tasty food and beautiful views. – Leilani Osmundson

Outdoorsy types and museum buffs should plan on spending at least one day on the Bygdøy peninsula. This region 3 miles west of central Oslo is home to some of the city's best museums, including the Fram Museum, the Viking Ship Museum and the Norwegian Museum of Cultural History. The peninsula's southern tip is especially popular in the summer when locals and tourists alike flock to the area's beaches and take advantage of its walking, jogging and bike trails. Huk beach also features a sand volleyball court available for free on a first-come, first-served basis.

U.S. News Insider Tip: Allow plenty of time – at least two hours – to explore the large range of exhibits here, including  "TIMESCAPE 1600-1914," which features gorgeous displays with digital explanations of unique items (such as a tiny sewing kit within a velvet-lined walnut). – Leilani Osmundson

At the Norwegian Museum of Cultural History, visitors can learn about traditional Norwegian architecture, early farm life and more. Several buildings are worth checking out at this open-air museum, including the 13th-century Stave Church from Gol and the medieval-style Setesdal Farmstead. Travelers will also spot reenactors in period attire participating in traditional dances, crafts and other activities every summer.

Nestled within Palace Park at the western end of Karl Johans gate, the Royal Palace draws history buffs, architecture enthusiasts, political junkies and those who enjoy learning about European royals. This grandiose structure, which was first used by King Oscar I in 1849, continues to serve as the home and office of Norway's monarchs. Most members of the royal court also work here, and foreign heads of state regularly stay on-site during official visits.

Several previous visitors praised this expansive property, citing its beautiful gardens and exquisite exterior as highlights. Those who arrived in the summer and toured the palace also raved about the lovely rooms and informative guides. But remember, no photography is permitted inside and tours – which are only offered from late June to mid-August – fill up fast. To ensure availability, past travelers suggest buying tickets in advance on Ticketmaster's website. Tour passes are sold starting on March 1. If you're unable to snag a spot on a tour, consider visiting at 1:30 p.m. when the changing of the guard ceremony takes places.

U.S. News Insider Tip: You don't have to watch an opera to enjoy the opera house. Make sure to climb the building up to the roof for incredible views of the city and harbor. – Leilani Osmundson

Music lovers and architecture enthusiasts alike won't want to miss a visit to this modern opera house. Located in the western part of Gamle Oslo, the Oslo Opera House features a contemporary design inspired by glaciers floating in the adjacent Oslo Fjord. Noteworthy details include floor-to-ceiling windows, wooden interior accents and an asymmetrical roof that visitors can walk on. The venue hosts performances by The Norwegian National Opera and Ballet, Norway's largest music and performing arts organization, throughout the year.

Established in 2003, the National Museum of Art, Architecture and Design is actually a merger of four formerly separate museums. Only the National Gallery, Villa Stenersen, Mellomstasjonen (the information center) and The National Museum – Architecture remain open to the public as the property works toward opening a new, larger facility in downtown's Vestbanen train station. In each of these buildings, travelers can admire extensive collections about art and architecture. Noteworthy items include Edvard Munch's "The Scream" and "Madonna" paintings.

All three buildings earn praise for their exhibits, but it's the National Gallery that woos the bulk of the National Museum of Art, Architecture and Design's visitors. Travelers say the museum's iconic Munch pieces can't be missed but also recommend perusing the other paintings, sculptures and drawings displayed inside. Lines to view "The Scream" can get long, especially in the afternoon on summer days, so consider arriving early. To save even more time, purchase your ticket in advance on Ticketmaster's National Gallery page.

Named after one of Norway's oldest vessels used for North and South Pole expeditions, the Fram Museum offers a glimpse at Norway's polar history. Inside, visitors will find exhibits about various polar explorers (think: Fridtjof Nansen and Roald Amundsen) and the Northwest Passage, but the museum's two polar ships are its highlights. Used in expeditions in the 19th and 20th centuries, the Gjøa and the Fram take up the bulk of the museum's floor space. Travelers are welcome to climb aboard and explore each vessel's decks. The Fram's cabins, lounges, cargo hold and engine room are also open to the public.

Whether you have an interest in polar history or just want to find an air-conditioned activity suitable for kids, reviewers say the Fram Museum is well worth a visit. Many museumgoers rave about the property's ships and accompanying information, describing the exhibits as so interesting that you could easily spend a few hours here. Several visitors also suggest taking the ferry to and from the property during the summer months since it docks across the street.

Whether you love skiing or just want to temporarily escape the hustle and bustle of downtown, odds are you'll enjoy exploring the Holmenkollen Ski Museum. Located in Oslo's Holmenkollen neighborhood roughly 6 miles northwest of the city center, this museum is the world's oldest dedicated to skiing. More than 4,000 years of skiing history are explored in exhibits that display everything from skis used during polar explorations to information about how climate change is expected to impact future skiing conditions. The world's longest skis – which measure 147 inches long – and one of the oldest skis ever found – it's believed to be from around A.D. 600 – are also available for viewing.

Although a few recent visitors found the museum itself to be boring, many felt its displays were informative and thoughtfully laid out. However, the highlight for most former museumgoers was the adjacent Ski Jump. Built in the early 2000s to replace previous iterations of the original jump constructed in 1892, the current structure is made of steel and features a sleek, cantilevered design. Its glass facade protects skiers and spectators from the wind, and a tilted elevator travels up the jump to bring travelers to its public viewing platform. Past visitors highly recommend heading to the top to take in the city views and speed down the zip line – if you're feeling brave.

Across the street from the ferry pier in the heart of Oslo's Sentrum neighborhood lies Oslo City Hall, a government building best known for annually hosting the Nobel Peace Prize ceremony. This 20th-century building, which was designed by Norwegian architects Arnstein Arneberg and Magnus Poulsson, features a brick facade and two towers, including one with a 49-bell carillon that plays hourly. Inside, visitors will find multiple works of Norwegian art that depict scenes of the country's history and culture.

Travelers have mixed feelings about Oslo City Hall. Some were less than impressed with the structure's austere exterior. However, many praised the property's interior, especially its impressive marble walls and thought-provoking murals. In fact, several visitors describe the property as a surprising must-do. For a complete overview of the building, plan a summer visit. Between June and August, free guided tours are available at 10 a.m., noon and 2 p.m. daily.

Overlooking Oslo Fjord in downtown Oslo, Akershus Fortress – which is composed of a medieval fortress and a Renaissance castle – has been a fixture in the city for more than 700 years. For most of that time, its primary purpose was to defend the city from foreign invaders – something it did well, as no foreign military ever managed to capture it by force. The fortress also served as a prison, a church and a royal residence for a time. Now, it's home to a visitor center, government offices and two museums: the Norwegian Armed Forces Museum and the Norway Resistance Museum.

Previous travelers praised the property's breathtaking water vistas and impressive architecture. Others raved about the castle's interior, which reopened in January 2019 after undergoing renovations. Keep in mind, entry to the castle costs 100 kroner (less than $12) per adult and 40 kroner (about $4.50) for each child between 6 and 18. Visitors with an Oslo Pass and kids 5 and younger get in for free. Ticket prices cover use of an English audio guide.

Just south of the sprawling Vigeland Park lies the Vigeland Museum, an art museum filled with sculptures, portrait busts, sketches and more. The property is named after local artist Gustav Vigeland, whose former studio and apartment were converted into a museum following his death in 1943. The attraction's collection primarily features works made by Vigeland, including approximately 12,000 drawings, 1,600 sculptures and 420 woodcuts. The museum's standout exhibit is its room of original plaster models Vigeland used to create the 200-plus sculptures in Vigeland Park.

Although a few former visitors were not impressed with Vigeland's sculptures, many suggest checking out the property, especially if you have an Oslo Pass (which covers the museum's entrance fee). One recent traveler noted that additional information (in English) is available on laminated cards inside each exhibit, but for even more background about Vigeland and his pieces, you can sign up for a guided group tour in English. Rates start at 500 to 1,000 kroner per group, depending on the number and age of participants.

For an in-depth look at one of the world's most coveted awards, head to the Nobel Peace Center. This institution pays homage to the iconic Nobel Peace Prize, which is presented every year at Oslo City Hall, through various exhibits. Temporary collections touch on topics like the threat of nuclear weapons and individuals subjected to human rights abuses, while the center's permanent "Nobel Peace Prize and the Laureates" exhibit offers videos, photos, texts and animations about every Nobel Peace Prize winner's life and work. Prior award recipients include Nelson Mandela, Mother Theresa, the Dalai Lama and Martin Luther King Jr.

Reviewers describe their visits to the Nobel Peace Prize as hit or miss. Although some say its touching exhibits make it the best attraction in Oslo, others lament the poorly organized ticket desk and confusing tour guides. Overall, many travelers only suggest visiting if you have an Oslo Pass, since admission is covered in the pass fee.