The museum's home was settled at  the Montague House in Bloomsbury since 1754. Soon after this facility became too small to display and store the museum growing collection and plans were made to add extra buildings. The first addiction was the Townley Gallery for classical sculpture , but was later torn down to make room for the Smirke Building, which is today the core of the building.

Sir Robert Smirke conceived the idea for the Smirke Building in Greek revival style by 1823, but, It was not completed until thirty years later.

It was originally built to house the personal library of King George III. 

A circular reading room with a dome on top was added in 1857, while King Edward VII's Galleries, a Beaux Arts style addition, only became part of the museum in 1914.

The Parthenon Galleries were built to house the Parthenon sculptures and opened in 1939. However, because of many damages occurred during World War II, the structure had to be totally rebuilt. It reopened, after a massive refurbishing, in 1962. 

Finally, the Queen Elizabeth II Great Court opened in 2000. This 8000 square meters area, enclosed by a glass roof, creates an indoor courtyard with the above mentioned museum's circular reading room in the center. This design made by Norman Foster and Partners makes it very similar to the entrance way below the Louvre Pyramid in Paris.

The Elgin Marbles, the collection of marble sculptures that were taken from the Parthenon in Athens, is one of the museum's most famous attractions. They are located in the dedicated Parthenon Galleries. 

The sculptures, also known as the Parthenon Marbles, were obtained by Thomas Bruce, the 7th Earl of Elgin and diplomat in Constantinopal in the Ottoman Empire, which at that time included Greece.

Earl Elgin obtained the permission "to take away any pieces of stone with old inscriptions or figures ", to prevent further damages by the Turkish.

Lord Elgin's collection was at first displayed at his own house, but in 1816 the House of Commons decided to purchase the collection and gave it to the British Museum.

Another important section of the British Museum is the large Egyptian collection. Besides many sarcophagi and statues, including an enormous one of Pharaoh Ramesses II, the collection includes the famous Rosetta stone, used by the archeologist Jean-François Champollion to decipher the hieroglyphic writing.

The British Museum is also popular for its very large collection of Egyptian mummies.

The Assyrian collection features sculptures from the palaces of the Assyrian kings at Nimrud, Khorsabad and Nineveh. The enormous winged bulls from the palace of Sargon II are especially impressive.

The Museum is closed on 1 January and 24, 25 & 26 December, but open every other day of the year.

Museum galleries are open daily 10.00–17.30, and most are open until 20.30 on Fridays. Closing starts from 17.20 (20.20 on Fridays).

The Great Court, including the Information Desk, is open daily 09.00–18.00 and until 20.30 on Fridays. The Ticket Desk is open daily from 09.00-17.00 and until 19:45 on Fridays.

Some collectors claimed this was perfectly legal, as they removed items with the connivance of the Ottoman authorities - that had taken over Greece at the time. Many collections of Parthenon you can find in the world’s museums today were acquired in this way. The most famous and significant was brought to London beginning in 1803 by the former British ambassador to the Ottoman Empire, the nobleman Thomas Bruce—more commonly known as Lord Elgin.

On July 6, 1801, Lord Elgin received authorization to remove whatever pieces were of interest to him—or at least that’s how Elgin interpreted this now controversial passage from the sultan: “When they wish to take away some pieces of stone with old inscriptions and figures, no opposition be made.” 
Finally in 1803, the huge collection of marbles was packed and loaded into ships at the port of Piraeus to await their passage to England.

After having brought the statues and reliefs to England, Lord Elgin proposed to put them on public display and “restore” the statues. Elgin hoped to re-create the missing sections of each piece. He called the most important neoclassical sculptor of the time, Antonio Canova to do it. Canova, a Venetian, refused to touch the treasures, protesting: “It would be a sacrilege for any man to touch them.” From 1807, Elgin exhibited the marbles that had arrived in Britain in a house that he rented downtown London. The display attracted a large number of people, artists and academics.

The costs of shipping the marbles were paid by Lord Elgin. He calculated he had spent a total of £74,000 in expenses — more than a million dollars in today’s money. Despite his title, Elgin was not a very rich man, especially after his divorce. This is why he proposed the British government to buy the collection. The country was divided among those who considered the Government should by the treasure for the nation, tand hose who considered them a waste of money, and those like the poet Byron who accused Elgin for taking them from their motherland.

After they had been sold, the marbles spent several years in a temporary house, and later moved to the Elgin Room in the British Museum in 1832.

Since 1832, successive Greek governments have petitioned for the return of the Parthenon marbles. The new Acropolis Museum of Athens, which opened in 2009, includes a specially designed space to house the marbles for the day—fervently awaited by many Greeks—they are reunited with other treasures from the Parthenon and the Acropolis. But, the British Museum has always refused all requests to send them back. The Parthenon marbles have become the most visible, and notorious, collection of Acropolis artifacts still housed in a museum outside Greece and the justification for not sending them back is that such objects are emblematic of European civilization , not just of Greek heritage.