Here's a great aerial view of one of the most well-known castles of Slovakia, compliments of contributor martini. It's called Trenčín Castle (Trenčiansky hrad), and it's in a town, district and region of the same name in the northwestern corner of the country. Like many castles in Central Europe, it's a hilltop structure built on older Roman fortification. Its rotunda likely dates to the 8th-9th century AD, and most of the rest of the site dates to the late Middle Ages. The castle is open to touring and is home to a castle museum.