The Lotrščak Tower is a fortified tower located in Zagreb

Zagreb

Zagreb is the capital and the largest city of the Republic of Croatia. It is in the northwest of the country, along the Sava river, at the southern slopes of the Medvednica mountain. Zagreb lies at an elevation of approximately above sea level. According to the last official census, Zagreb's city...

, Croatia

Croatia

Croatia , officially the Republic of Croatia , is a unitary democratic parliamentary republic in Europe at the crossroads of the Mitteleuropa, the Balkans, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Croatia covers ...

, in old part of town called Gradec

Gradec, Zagreb

Gradec or Grič is a part of the Zagreb, Croatia, and together with Kaptol it is the mediaeval nucleus of the city. It's situated on the hill of Gornji Grad.- History :Gradec was given a royal charter by King Bela IV in 1242...

 or Gornji grad (Upper town). The tower, which dates to the 13th century, was built to guard the southern gate of the Gradec town wall. The name is derived from Latin campana latrunculorum 'thieves' bell', referring to a bell hung in the tower in 1646 to signal the closing of the town gates.

In the 19th century a fourth floor and windows were added to the Lotrščak Tower and a canon was placed on the top, called the Grič cannon

Gric cannon

The Grič cannon is one of the Zagreb landmarks. Since 1 January 1877 the cannon is fired from the Lotrščak Tower on Grič to mark midday. The cannon was to give the sign for exact noon for the bell-ringers of the city's churches.-References:*...

. The canon is fired every day at noon.