<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 in stone, and it became the only bridge across the River Thames. In the 16th century, the bridge was the site of a battle between the forces of the king of England and the French army. In the 19th century, the bridge was rebuilt again, and in the 20th century it was renovated.