Wales is a country in the South West of the United Kingdom known for its rugged coastline and hilltop national parks. Language, Welsh, and Celtic culture have unique characteristics. Cardiff, the capital, is a sophisticated coastal city with a lively nightlife and a medieval castle with interiors decorated in a neo-Gothic style. In the northwest, Snowdonia National Park has lakes, glacial formations, hiking trails and a railway line that reaches the summit of Snowdon.