A 'temple to nature', the museum was purpose built in the 1870s to house the nations natural history collections. The museum currently holds about 70 million specimens and they say that number is still growing. Only a fraction of them are on display. The storerooms sound equally impressive.
Much of this is due to the original contributor, Sir Hans Sloane ( 1660-1753). A London doctor, naturalist and collector he amassed 80,000 objects and books which filled his London home. Imagine trying to tidy up around his place. He left his collection to the nation in his will which in turn formed the basis for the Britsh Museum in Bloomsbury. In 1881 it was 'all hands on deck' to move the collection to its current home, the Natural History Museum in South Kensington. The zoological collection alone took more than 97 days and 394 trips by horse and cart. Just imagine!
I must say...it is a spectacular building inside and out and deserves many trips to appreciate all its splendour. My only advise is to avoid the school holidays unless you have curious children of your own!
Reference from Natural History Museum