Known as Kolonthota, the area became notable as the site of the first landings of the Portuguese in the early 16th century. The fort constructed by the Portuguese was conquered by the Dutch in 1656. Following the British acquiring control of the Dutch-controlled areas on the coast of the island, the fort became the center of its administration. Many buildings in the fort area were home to the British administration of the island. As well as the heart of the administrative capital, the fort area became the heart of the commercial capital too. The fort area is a mixture of buildings from many eras of the cities past. Today, the Fort is the central business district of Colombo and is also home to a few government departments and offices including the Presidential Palace, Presidential Secretariat Office, and Ministry of Foreign Affairs. The fort is served by the Fort Railway Station, which is a major rail hub in Colombo.

The current 29-metre-high (95 ft) lighthouse was built in 1952 after the Old Colombo Lighthouse was deactivated when its light became obscured by nearby buildings as part of the Colombo Harbor Expansion project. Located at its base is a naval gun battery that is used by the Sri Lanka Navy for its traditional gun salutes. Due to the panoramic view of the Indian Ocean it offered, it became a city landmark.

Built in the 19th century, the Gangaramaya Temple is one of the most important temples in Sri Lanka, being a mix of modern architecture and cultural essence. Its architecture demonstrates an eclectic mix of Sri Lankan, Thai, Indian, and Chinese styles. Most notable for tourists is the architecture of the Simamalaka Shrine, which was built with donations from a Muslim sponsor to the design of Geoffrey Bawa. It has the main features of a Vihara (temple), the Cetiya (Pagada) the Bodhitree, the Vihara Mandiraya, the Seema malaka (assembly hall for monks) and the Relic Chamber. Today Gangaramaya serves not only as a place of Buddhist worship; it is also a centre of learning.

It is the oldest and largest park of the Port of Colombo. The park was built on land donated to the Colombo city by Charles Henry de Soysa during the British rule of Sri Lanka, and used to be named "Victoria Park" after Queen Victoria. During World War II it was occupied by the British Army with Australian 17th Brigade based at Victoria Park. After the war the park was restored and open to the public in 1951. The park features include a huge Buddha statue and a series of water fountains.

The National Museum of Colombo is the largest museum in Sri Lanka. It holds collections of much importance to Sri Lanka such as the regalia of the country, including the throne and crown of the Kandyan monarchs as well as many other exhibits telling the story of ancient Sri Lanka. The Colombo museum as it was called at the beginning was established in 1877 and founded by the British Governor of Ceylon (Sri Lanka) at the time. During the period between 1877 and 1999, the authorities of the museum took various steps to display the cultural and natural heritage of the country. Nine branch museums were ultimately opened, and a school science programme and a mobile museum service are also in operation. Notably, the museum has a copy of the Statue of Tara, a three-quarter life size statue of Tara currently held in the British Museum. The crown jewels and the throne of the last King of Kandy, which were returned to Sri Lanka by the British Government, were added to the museum collection.

Located on the Square is the Independence Memorial Hall, which is a national monument built for commemoration of the independence of Sri Lanka from the British rule with the restoration of full governing responsibility to a Ceylonese-elected legislature on February 4, 1948. Located at the head of the monument is the statue of the first prime minister of the country Rt. Hon. Don Stephen Senanayake "The Father of the Nation". Most of the annual National Independence Day celebrations have been held here. Currently it is the venue for religious events and annual national day celebrations.

Completed in 1902, St. Lucia's Cathedral is the seat of the Archbishop of the Roman Catholic Archdiocese of Colombo in Sri Lanka. It traces its origins to a small structure for worship built during Dutch occupation and is considered the oldest and largest parish cathedral in Sri Lanka. The facade rests on massive ionic columns and is adorned with seven statues. Silhouetted against the sky is the cross on the concrete lantern crowning the dome, the pinnacle of the cathedral. The view of the cathedral from the choir loft is a grand one, with the episcopal throne of the Archbishop of Colombo standing out as a majestic highlight in the sanctuary below.

Known colloquially as the 'Samman Kottu Palli' or 'Red Mosque', Jami-Ul-Alfar Mosque was built in 1909 in the Indo-Saracenic style by the Pettah Muslim community to fulfill their required five-times-daily prayer and Jummah on Fridays. It is one of the oldest mosques in Colombo.

The Colombo Dutch Museum is a museum that covers the history of the Dutch colonial rule in Sri Lanka. The two storey colonnaded building that houses this museum was constructed during the Dutch occupation of Colombo (1656 - 1796) and was the formal residence of the Governor of Dutch Ceylon. This museum was opened to the public in 1982. This building embodies the unique architectural features of a colonial Dutch town house. The museum while displaying the Dutch legacy with the artefacts including furniture, ceramics, coins and weaponry, portraying the various facets of contemporary life and culture.

The Pettah Floating Market is located on Bastian Mawatha in the Pettah neighborhood and consist of 92 trade stalls, with a number of the stalls established on boats on Beira Lake. The unique simple architecture of the stalls along the canal with grey cemented floors and minimalistic décor is meant to reflect the calm and undisturbed water of lake. The market is steps away from the Bastian Mawatha Bus Station.

The Nelum Pokuna (Lotus Pond) Mahinda Rajapaksa Theatre (previously the National Performing Arts Theatre) is a performing arts centre opened in 2011. The architecture is inspired by the 12th century Nelum Pokuna (Lotus Pond) in Polonnaruwa. Built by King Parakramabahu the Great, Polonnaruwa's Nelum Pokuna is shaped as a stylised eight-petalled lotus flower. The theatre is equipped with ultra modern facilities such as an auditorium with 1,288 seats, a library, and training facilities. Notably, in 2013, the Theatre hosted its first symphony orchestra concert, by the Commonwealth Festival Orchestra, with 87 musicians from the UK, India and the Symphony Orchestra of Sri Lanka.