Fortaleza do Monte, Military fort on Monte Hill, Macau.

The fort rises 52 meters (171 feet) above sea level, featuring walls that measure 2.7 meters (9 feet) thick and reach 9 meters (30 feet) in height. The structure includes several bastions at the corners equipped with historic cannons that provide panoramic views over the city. Within the walls stand remains of barracks, underground storage chambers, and wells that demonstrate the original military layout.

The Jesuits built the fort between 1617 and 1626 to protect their Macau properties, mainly from pirates. It served as the residence of Macau's governors from 1623 to 1749. In 1622 its cannon helped repel the Dutch invasion attempt. A restricted military area until 1965, it later housed a weather observatory and, since 1998, the Museum of Macau.

The fort's gate faces south, and the entrance passage once served as a gunpowder magazine. Since 1998 the centre of the enclosure has held the Museum of Macau, while the top level is a garden. From 2023 the fort is the only place in Macau where typhoon signal No. 9 or 10 is hoisted.

The fort opens daily without admission charge, with early morning visits offering fewer crowds and cooler temperatures. Visitors reach the site by walking from the Ruins of São Paulo via a stairway or taking a bus to Monte Hill. The grounds feature paved pathways, though some areas have steps that may limit wheelchair access to certain sections.

Legend holds that a single cannonball fired from the fort by an African slave or a priest struck a Dutch powder magazine, triggering an explosion that ended the 1622 attack. Beneath the buildings lies a complex network of underground tunnels and cisterns capable of storing over 10,000 cubic meters (353,000 cubic feet) of water to supply the garrison during extended sieges.