<human>:  Why is it called the London Bridge?
<bot>: The bridge was built in the 12th century, and the city of London grew up around it. In the 14th century, the bridge was rebuilt, and in the 15th century, it was rebuilt again. In the 16th century, it was destroyed by the Great Fire of London, but was rebuilt again. In the 18th century, it was rebuilt once more, and it is still in use today.