This concrete tower lurks within the waters where the rivers Medway and Thames merge like a ghost of its planned glory. The structure, which is abandoned and looks rather unstable now, was built to defend the mighty river from the threat of a French naval invasion.

In the 1850s, the British feared that their foes in France would use the winding waterways to launch an attack on England. Important dockyards dotted the country’s southeastern coast, and the military wanted to ensure that these strategic locales would remain safe.

The Grain Tower Battery was built to stand like a concrete guardian stationed just off the shore of the Isle of Grain. It’s the last-built example of this particular type of gun tower, thanks to rapidly advancing technological improvements. By the time the tower was completed in 1855, newer rifled muzzle loaders had rendered it all but obsolete.

It was soon repurposed as a communications tower. The tower was briefly used during World War I and again during World War II. However, it was decommissioned in 1956, just over a century after it was opened. Now, the tower’s future remains uncertain. It’s been in private hands since 2005, but as of yet no one has done anything with it so it just stands within the water, unused and largely isolated from the shore.