It's one of the world's great museums. With over 8 million pieces in its permanent collection, it features a remarkable representation from around the world. The ways in which some of the artifacts were acquired--some say pilfered, some say protected--is rightly controversial. A sizable portion of the collection was made possible by the long reach of British colonialism. But there's little argument that the British Museum is an astonishing resource for understanding human history and culture.
The museum is conceptually similar to the Met in New York. You won't find any dinosaur skeletons here or space shuttles. But you will find plenty of Egyptian mummies, ancient Roman and Greek artifacts, statues of Asian deities, and coverage of the span of human inhabitation of the British isles.