four go down the thames: Places

Greenwich

Greenwich is located at a latitude and longitude of 51° 28' 38" N and 0º 0' 0" E/W (by definition). It is 6 miles east of London on the south bank of the River Thames.

The Cutty Sark is the most famous tea clipper built, and is the only one to survive. She is now in dry dock at Greenwich. As a tea clipper the Cutty Sark played an important role in the world tea trade.

more after the jump..

Thames Barrier

The Thames Barrier is a flood defence mechanism that protects London from tidal floods. It can shut of the river here within 30 minutes in the event of a dangerous tidal surge.

The barrier was built to prevent a repeat of the devastation caused in 1953, when high tides and a storm combined to create a surge of 3.2 metres that killed 307 people and left parts of the U.K. under water. 4,000 men and women were engaged in the building work, which cost nearly 500 million pounds.

The barrier is built across a 1716 feet (520 metre) wide stretch of the river and divides the river into six navigable and four smaller non-navigable channels between nine large concrete piers. The piers are founded on solid chalk, over 50 feet below the level of the river.

The barrier is a series of ten separate rotating gates positioned end-to-end across the river. When there are high tides, with high waves caused by storms, the gates are lifted to stop water travelling up the Thames estuary.