Cleopatra's Needle is a large stone obelisk that has sat on the Victoria Embankment opposite the Savoy since 1878. It's thought the obelisk, and its two sisters in Paris and New York, were originally carved c. 1475 B.C, so they are genuine ancient Egyptian artefacts.
However, none of them have any connection to Cleopatra whatsoever, and in fact pre-date her by about a millennium! When the London obelisk was carved, it was inscribed with the names of pharoahs and gods. Cleopatra, the last pharaoh of Egypt, had her name added later; but that's the only connection between the two.
The 68.5 metre high obelisk was cut from a single block of stone and is so heavy that transporting it to England proved to be exceptionally difficult. The first attempt ended with the needle at the bottom of the ocean, and it had to be dredged up and placed on a second boat. A fourth needle, donated to the French, still resides in Egypt as they can't figure out how to transport it!
The sphinxes which surround the needle were not part of the original installation; they were added in 1880 by sculptor George Vulliamy. Today, the sphinxes and the pedestal show blatant signs of bomb damage - unusually not from the Blitz, but from a Zeppelin-dropped bomb in the First World War.