Mount Fortress built in 1626 stands on top of Mount Hill, which rises 52 metres above sea level. The fortress covers an area of 10,000 square metres, in the shape of a trapezoid. The four corners of the fortress protrude to form bulwarks. The north-eastern, south-eastern and south-western walls are built on 3.7 metre wide granite bases. The walls, 9 metres high narrowing upwards to 2.7 metres wide at the top, are made of solid rammed earth, further strengthened by a thick stucco of ground oyster shells. The parapet sections were crenulated for the installation of 32 cannons and the two corners of the south-east wall have watchtowers.