Where: London's Roman Amphitheatre
In 1988, archaeologists from the Museum of London made the discovery of their careers. Below Guildhall Yard in the City were the remains of what appeared to be a Roman amphitheatre. And just like a typical amphitheatre of its day, it is believed it was host to savage animal contests, public executions, and gladiator battles.
The surviving ruins are 20 feet below ground, and include a stone entrance tunnel and parts of the arena walls, as well as a circle of black paving stones marking the original extent of the outer wall. The amphitheatre was dismantled in the 4th century after the Romans left, with most of it being used as materials for other constructions. That makes the remnants of the venue around 1,700 years old. The site is now part of an interactive museum you can see when visiting the Guildhall Art Gallery, and if you want to really delve into what went on here, take part in one of the museum's guided tours.