Mount Fortress, built in 1617-26, occupies a hilltop to the east of the ruins of St. Paul′ s. It was constructed by the Jesuits as part of a complex which also included the college and church of St. Paul′ s. The canons were used only once, when the Dutch invaded Macau in 1622. This was also the first residence of the governors of Macau. Over the following decades trees grew from the platform of the fort, which was transformed into a public park where residents and visitors came to enjoy the views. The only building was an office of the Meteorological Department until 1998 when the three-level Macau Museum, focusing on the history of Macau, was built into the fortress hill.

Mong Há Fort, situated on Mong Há Hill at the northern end of Macau, is a newer fortress, built in anticipation of a Chinese invasion following the Anglo-Chinese War in 1841. It was completed in 1866 and was in active service until the 1960′ s, when it was abandoned. Today the area has been turned into a park with flowerbeds, grassy slopes and walkways surrounding the old fortress walls. It provides a quiet refuge for people living in the nearby neighborhoods, and good views of the north end of the city.

Built 1629 on the site of a battery which sank one of the warships' The Golias' of the Dutch invaders, the original fortress of S. Francisco stood at the end of old Praia Grande, facing the Taipa channel. Its armaments included a culverin, which could fire 35-pound iron shots a distance of one and a half miles (the width of the channel). Little more is known of the original fort or the convent of S. Francisco, which was attached to it.

Both fort and convent were demolished to make way for new barracks in 1864, to house the Battalion of the First Line, brought in as defence against a Chinese attack which never came. The barracks survive today as headquarters for the Security Forces and sections of the Police Force. They present an attractive, colonial facade of pink-washed stone with white trim. Inside are offices and meeting rooms around a flag-stoned courtyard, in the spacious lobby are display cases filled with old prints and pictures of the previous fort and convent, a collection of old weapons and other.

Guia Fortress, built in 1622-1638, occupies the top of Guia Hill, the highest point in Macau. It was designed to defend Macau from attacks from the sea, but because of its position overlooking the entire city, its chief value has been as an observation post. It originally contained barracks, a water cistern, ammunition and equipment stores, the commander's house, and a chapel dedicated to Our Lady of Guia. Today the Fort's most prominent feature is the lighthouse, built in 1864 and the oldest on the China coast. It is 15 metres high and has a light which can be seen for around 20 miles in clear weather. Near the lighthouse is the chapel which contains an image of the Virgin Mary, a few antique pictures, and vestiges of paintings that date back to the construction of the chapel in 1622. Also nearby is a post where signals are hoisted to warn of an approaching typhoon. In earlier times storm warnings were announced from the bell-tower of the chapel.