Kutná Hora

Kutná Hora needs 1 day: the Sedlec Ossuary (Bone Church), decorated with the bones of over 40,000 people, on one end, St. Barbara's Cathedral, a Gothic masterpiece funded by local silver miners, on the other. April-October is best. It's cheaper than Prague, just 1 hour away by train. In the 14th century it was one of the richest cities in Europe thanks to its silver mines, with its own currency (the Prague groschen) minted there that circulated across much of the continent, and today it's a UNESCO World Heritage Site for that legacy.