The Tower of London is the most interesting fortress in Great Britain; it has a history equalled in interest by few fortresses in the world. The Acropolis at Athens and the Capitol of Rome are far more ancient, but they are fortresses no longer. The only rival in this respect that occurs to me is the massive tower at the Western Gate of Jerusalem. It was probably built by King David, and enlarged by Herod; and it is a military castle at this day. So is our Tower, and it was built for that use.