St. Mary's Church (Polish: Bazylika Mariacka, German: St. Marienkirche), or formally the Basilica of the Assumption of the Blessed Virgin Mary.
Its construction began in 1343 and was completed in 1502.
It is 105.5 metres (346 ft) long, and the nave is 66 metres (217 ft) wide. Inside the church there is room for 25,000 people.
With its volume between 185,000 m3 and 190,000 m3 it is currently one of the two or three largest brick churches in the world.
The massive tower, well visible on the city's skyline, is about 80 meters high.
There is an observation platform on top of it.