Besides the Marbles, the British Museum houses the Rosetta Stone, key to reading ancient Egyptian hieroglyphics; the Black Obelisk from Calah and Ninevah; gold, silver, and shell work from Ur; Sutton Hoo ship's treasure from the famous burial site; and Chinese ceramics from the Ming dynasty. You can find items here from every corner of the denver selfie museum and from many archaeological sites in England herself.
But the British Museum is much more than a repository for ancient things. It's also one of the largest libraries in Britain. Until about 1997, half of the National Library's holdings were stored at the museum. The Reading Room has been recently refurbished, with a new reference collection and state of the art computer systems. You can visit the Great Court, a two acre glass-domed hub of culture within the museum. Another new edition, is the Ethnographic Galleries, collections on life in Africa, Asia, and the Americas. And at last, if you just get tired of the history and culture, you can visit the shops and the restaurants inside the Museum.
If you visit the British Museum while in London, arrive early; it's as large as many malls. Spend your first hour or two just wandering in the halls and staring at everything. Later, focus on the Egyptian, Mesopotamian, and Greek sections; they are the homes of the by far most fascinating collections of the British Museum. Huge winged lions that once guarded Assyrian palaces now guard the gateways to these collections. In the Egyptian section, you can find the Rosetta Stone as well as mummies and a fantastic collection of treasures from Egyptian tombs. In the Nimrud Gallery, you'll find royal propaganda reliefs (some things never change in Iraq!) and wounded lions.
But the best section of all is the Greek section. Starting with the most simple and primitive Cycladian fertility figures (the little fat women with exaggerated female features), moving to painted vases and ultimately to the great Elgin Marbles, the Greek section really gives you a feel for the vast history that belongs to Greece.