Cer is a mountain (687 m) situated in Serbia (100 kilometers west of Belgrade) where from 12th till 19th of August 1914 the world war one battle of Cer was fought between Serbia and Austria-Hungary. In history it is also known as battle for Jadar, because the main operations were held near the river Jadar estuary. It was the first battle won by the allied forces (France,Russia and Serbia) against the central forces (Germany, Austria-Hungary) in the world war one. Although the battle lasted for only seven days, it is estimated that more than 16.000 Serbian and over 25.000 Austro-Hungarian soldiers died. Nowadays Mountain Cer is a favorite backpackers destination. Historical artifacts can be found in a museum located in the town of Sabac 30 kilometers away.