Tower of London

The Tower of London is guarded by characteristically dressed guards, called Yeomen Warders, or more popularly beefeaters.

An excerpt from the article 21 facts about Tower of London

This guard was established in 1485 by Henry VII. Only candidates from among the yeomen were engaged in it - middle peasants who owned horses, so that they could take part in the fight on horseback. Their duty was to protect the castle, which consisted of two tasks: guarding the prisoners and guarding the treasures and crown insignia kept there.