Because the original bridge was the ONLY bridge in London at that time.
London Bridge. The Olympic rings are on Tower Bridge - not London Bridge.
London Bridge spans the River Thames
London Bridge
London Bridge
The community of London Bridge in Virginia Beach is named after the London Bridge in England. The name was chosen in the early 20th century when a local businessman, who was inspired by the bridge's historical significance, established a nearby bridge spanning the Lynnhaven River. The area has since developed into a residential community, retaining the name as a nod to its origins.
London Bridge
It is called Tower Bridge. Or you might be talking about the one that was on Harry Potter and the Half-Blood Prince, which is the wobbly bridge, but it's proper name is the Millenium Bridge.
ACOL
Tower Bridge and London Bridge.
Tower Bridge is east of London Bridge.
There are 107 bridges across the Thames - to many to name here
The London bridge