Brest (Belarusian: Брэст, IPA: [brɛst]; Russian: Брест; see also alternative names), formerly also Brest-on-the-Bug and Brest-Litovsk, is a city (population 312,950 in 2008) in Belarus at the border with Poland, where the Western Bug and Mukhavets rivers meet. It is the capital city of the Brest voblast. Being situated on the main railway line connecting Berlin and Moscow, and an intercontinental highway, Brest became a principal border crossing since World War II in Soviet times. Today it links the European Union and the Commonwealth of Independent States. Because of the break of railway gauge at Brest between the Russian broad-gauge system and the European standard gauge, all passenger cars continuing service beyond Brest must have their bogies changed here, and cargo in freight trains must be transshipped. Some of the land in the Brest rail yards remains contaminated as a result of the transshipment of radioactive materials here since Soviet days. There are several theories of the city name origin. The most common are as follows, * the name of the city comes from the Slavic root beresta meaning birch bark, * the name of the city comes from the Slavic root berest meaning elm, * the name of the city comes from the Lithuanian word brasta meaning ford.