The Marκellοs Tower dates from the 17th century. Ιt is considered to be part of the fortifications that protected the harbor and a watchtower used by the Venetians. In 1802 the tower was renovated by the fighter, member of the parliament, Spiridon Markellos from whom it took its name. During the revolution of 1821 the Tower of Markellos hosted Greek freedom-fighters and politicians, such as G. Koundouriotis, I. Kolletis, N. Mexis, K. Favieros and many more. From 1826 onwards, it functioned as the seat of government and housed the treasury of the Greek state, while during the Kapodistrias’ administration, it hosted various ministers.
Today, the Tower of Markellos belongs to the municipality of Aegina and is one of the island's main attractions. It houses the Kapodistrian Cultural Center of the Municipality and the Spyros Alexiou Social Awareness Centre. It also hosts a variety of painting exhibitions, lectures and other cultural events, during which the tower is open to the public.