This museum on Great Russell Street in London is exceptional in many ways. It is the second most visited museum in the world (behind the Louvre in France), and is one of the most comprehensive and extensive collections of human artifacts to be found anywhere, housing over 8 million works from an astonishing scope of cultures both alive and gone. The best part: the museum is free. Not only are the permanent exhibits free, but free "eye-opener" tours are given of each exhibit at various times during the day.
There are the controversial marble statues from the Parthenon, Inca and Aztec pottery, busts from Rome, Viking weapons, and countless other artifacts that tell the story of human history. This is a must see not only for those interested in British culture, but in how civilization in its many forms has developed over time. Allow yourself a full day to get the true scope of this place, especially if you're going over the weekend or when British citizens are on holiday. Also, be aware that special exhibits will have entrance fees and may be booked ahead of time on the official website to ensure entrance.