Eton College
United Kingdom, Berkshire, Eton
It is basically just one street which runs from the bridge (closed to cars since 1972) to the college, which started out as a school for poor local boys back in 1440. Back then the Thames could provide fine trout for the table. These days the schoolboys have to make do with hampers from fortnum and mason.
Tours of the college (founded by King Henry VI) last about an hour and cost just over a fiver per person. You will get to see ancient classrooms covered with grafitti from centuries of schoolboys. Ex-students include 18 former prime ministers, Boris Johnson (mayor of London) the actor Hugh Laurie and Prince William to name just a few.
Because this is a real school, tours only run intermittently so it is essential that you book in advance. Alternatively stump up £20,000 a year and send your sons to school at Eton.