St. Mark's Tower or Qalet Marku is a fortification

Fortification

Fortifications are military constructions and buildings designed for defence in warfare and military bases. Humans have constructed defensive works for many thousands of years, in a variety of increasingly complex designs...

 on the island of Malta

Malta

Malta , officially known as the Republic of Malta , is a Southern European country consisting of an archipelago situated in the centre of the Mediterranean, south of Sicily, east of Tunisia and north of Libya, with Gibraltar to the west and Alexandria to the east.Malta covers just over in...

 built by the Knights of Malta

Knights Hospitaller

The Sovereign Military Hospitaller Order of Saint John of Jerusalem of Rhodes and of Malta , also known as the Sovereign Military Order of Malta , Order of Malta or Knights of Malta, is a Roman Catholic lay religious order, traditionally of military, chivalrous, noble nature. It is the world's...

. It is a small watchtower that stands on Qrejten Point on the north shore of Malta. St. Mark's Tower has sight of Għallis Tower to the west, and Madliena tower

Madliena tower

Madliena Tower is a fortification on the island of Malta built by the Knights of Malta. A watchtower, it stands on high ground above the shore west of Ras L-Irqieqa on the north shore of Malta....

 to the east. The tower still stands and appears to be in reasonable condition.

It was one of the thirteen de Redin towers

De Redin towers

The De Redin Towers are a series of thirteen small fortified watch towers that Grand Master Martin de Redin of the Knights of Malta built on the island of Malta between the year 1658 and 1659...

 constructed during the reign of Grand Master

Grand Master (order)

Grand Master is the typical title of the supreme head of various orders of knighthood, including various military orders, religious orders and civil orders such as the Ancient Order of Hibernians and the Orange Order...

 Martin de Redin

Martin de Redin

Fra' Martin de Redin was a Spanish military and politician, and the 58th Prince and Grand Master of the Order of Malta.He became Grand Prior of the Order of Malta of Navarra in 1641, and Viceroy of Sicily in 1656....

.