Luxembourg is a small European country, surrounded by Belgium, France and Germany. It’s mostly rural, with dense Ardennes forest and nature parks in the north, rocky gorges of the Mullerthal region in the east and the Moselle river valley in the southeast. Its capital, Luxembourg City, is famed for its fortified medieval old town perched on sheer cliffs. With an area of 2,586 square kilometres (998 sq mi), it is one of the smallest sovereign states in Europe, about the same size as the US state of Rhode Island. The history of Luxembourg is considered to begin in 963, when count Siegfried I acquired a rocky promontory and its Roman-era fortifications known as Lucilinburhuc, ′little castle′, and the surrounding area from the Imperial Abbey of St. Maximin in nearby Trier. The present-day state of Luxembourg first emerged at the Congress of Vienna in 1815. In 2016 Luxembourgish citizens had visa-free or visa-on-arrival access to 172 countries and territories, ranking the Luxembourgian passport 6th in the world, tied with countries such as Canada and Switzerland. Luxembourg has an oceanic climate marked by high precipitation, particularly in late summer. The summers are warm and winters cool. Major destinations are historic Luxembourg City, the medieval castle of Vianden, Echternach with its abbey and the wine districts of the Moselle valley. The Mullerthal with its rocky cliffs in the east and the mountainous Oesling district in the Ardennes to the north are also favourites for outdoor enthusiasts.