Tower Bridge Chimney

The lowdown

Standing near the north end of Tower Bridge is what looks like an ordinary green cast-iron lamp post, but it has a secret. It is actually a disguised chimney, built to carry away smoke from a small fireplace in a guardroom that once stood below, where soldiers from the nearby Tower of London kept warm on duty.

The flue runs up through the column, venting where you would expect a lamp. Thousands of tourists pose by Tower Bridge without a clue to its real job. It is free to find, a delightful little piece of Victorian ingenuity hiding among the crowds.