Croatia (officially the Republic of Croatia) is a sovereign state at the crossroads of Central Europe, Southeast Europe, and the Mediterranean. Its capital city is Zagreb, which forms one of the country's primary subdivisions, along with its twenty counties. Croatia covers 56,594 square kilometres and has diverse, mostly continental and Mediterranean climates. Croatia's Adriatic Sea coast contains more than a thousand islands. The country's population is 4.28 million, most of whom are Croats, with the most common religious denomination being Roman Catholicism.