The Estonian Maritime Museum (Estonian language: Eesti Meremuuseum ) is located in the Fat Margaret tower in the old town of Tallinn. The museum presents history of ships and navigation in Estonia and related to Estonia. Other parts of the Maritime Museum are the mine museum and the Seaplane Harbour where museum ships are presented.
Fat Margaret was built in the early 16th century (from 1511 to 1530) during the reconstruction of the medieval city gate system. The etymology of the tower's name derives from the fact that it was the largest part of the city's fortifications with walls measuring 25 meters in diameter, 20 meters in height and up to 5 meters thick. Apart from being a fortification against would-be invaders to the port of the town, it was also built to impress outside visitors arriving by sea. The tower is a defensive structure at the end of Pikk tänav (Pikk Street). Together with the Suur Rannavärav (Great Coastal Gate), a sixteenth-century arch flanked by two towers, it served to defend the harbour of Tallinn. Later, it was used as a storehouse for gunpowder and weapons, and then transformed into a prison, and was the scene of an outbreak of violence during the 1917 Revolution, when the prison guards were murdered by a mob of workers, soldiers and sailors. The tower now serves a more peaceful function of housing the Estonian Maritime Museum which looks at the nation's seafaring history with a collection of nautical paraphernalia that spreads over four stories and a view of the old town and Tallinn's harbour and bay from its rooftop viewing platform.
Present exhibits include 
- EML Lembit - A World War II Kalev class submarine
- EML Grif - A Zhuk class patrol boat
- EML Kalev (M414) - A Frauenlob class Mine warfare vessel
- PVL 105 Torm - A storm class patrol boat used by the coastguard.
- Suur Tõll - a steamer-icebreaker built in 1914
- "Eesti Meremuuseum". Meremuuseum.ee. 2012-02-22. http://www.meremuuseum.ee/. Retrieved 2012-03-15.
- Tallinn Tourism. "Great Coastal Gate and Fat Margaret tower". Tourism Tallinn.ee. http://www.tourism.tallinn.ee/fpage/explore/attractions/az/newwin-place/print/id-174824. Retrieved 15 March 2012.