The River Thames is the most important river in England. There are more than 200 1 over the river. Tower Bridge has stood over the River Thames in London since the 1890s. It is the 2 bridge of all. 3 makes Tower Bridge so amazing? Why do so many visitors coming from 4 the world go to see it? It is because the walkway (人行通道) of Tower Bridge can open up in the middle. It does this to let big ships go 5 to the Pool of London. It is the only bridge in London that can be opened up to allow (允许) 6 to go through. If you are 7 enough to see the bridge with its two opening arms lifted (抬起) in the air, you will never forget it. You can also 8 the wonderful views (景色) of the river on the bridge. 9 its north side stands the Tower of London. Tower Bridge and the Tower of London both look very old, and you may think they are of the same age. However, you are 10. The Tower of London is almost one thousand years old, but Tower Bridge is only over one hundred years old.