A site of defense since the Iron Age, Newhaven Fort has seen a lot of local history. It was fortified during the Napoleonic Wars of the 1860s to prepare for an imminent invasion of the French. Its unique design comes from the fact that it was built into the contours of the land, instead of on top of it like a traditional fort or castle, which allows for numerous subterranean tunnels and chambers.

From its high vantage point over the English Channel, large guns were installed, and by the time the First World War broke out Newhaven Fort had become an integral part of protecting the South Coast of England, which played its part in sending six million tons of supplies across to France. During the Second World War the fort housed the thousands of soldiers who passed through the area. Its position to the harbor played a role in many key turning points of the conflict, including the D-Day landings of 1944.

After the World War II, Newhaven Fort fell into disrepair, and at one point in the 1960s it was nearly developed into a leisure complex. In 1979, it was declared an ancient monument and after a series of owners, it became the visitor attraction it is today. The fort is now full of interactive exhibitions, such as a blitz bomb shelter experience, and houses a vintage tearoom. Paranormal investigators regularly visit the fort to investigate the spooky goings on, particularly down in the caponiers, the huge tunnels built into the cliffs.