Landguard Fort
Built just outside Felixstowe, Suffolk at the mouth of the River Orwell, Landguard Fort was designed to guard the entrance to Harwich. The first fortifications from 1540 were a few earthworks and blockhouse, but it was James I of England who ordered the construction of a square fort with bulwarks at each corner.
In 1667 the Dutch landed a force of 1500 men on Felixstowe beach and advanced on the fort, but were repulsed by Nathaniel Darrell and his garrison of 400 musketeers of the Duke of York & Albany's Maritime Regiment (the first English Marines) and 100 artillerymen with 54 cannon.
A new battery was built in 1716, and a complete new fort on an adjoining site was started in 1745 to a pentagonal bastioned trace. New batteries were built in the 1750s and 1780, but the biggest change was in the 1870s where the interior barracks were rebuilt to a keep-like design, the river frontage was rebuilt with a new casemated battery covered by a very unusual caponier with a spectacular quarter sphere bomb proof nose. Several open bastions were enclosed, and a mock ravelin block constructed to house a submarine mining contingent.
During the Second World War, it was used as one of the balloon launch sites of Operation Outward. This was a project to attack Germany by means of free-flying hydrogen balloons that carried incendary devices or trailing steel wires (intended to damage power lines.) Between 1942 and 1944, many thousands of balloons were launched.
The Left Battery was converted into the Anti-aircraft Operations Room for Harwich in the 1950s.
The fort has been structurally consolidated and is open every day from April to the end of October. The Ravelin block houses Felixstowe museum.
The fort hosts a bird observatory, and is important for the study of bird migration.