Miskolc, Hungary

Miskolc sits at the foot of the Bükk Mountains in northeast Hungary and is the country's fourth-largest city, with roughly 150,000 residents. At Miskolctapolca, a 1.5-km artificial cave bath opened in 1959 holds year-round 30°C thermal water. The 18-hole Pálmalom Park features Europe's northernmost plane-tree avenue. The 13th-century Diósgyőr Castle rises with four 26-m corner towers and hosts medieval tournaments, while the 19th-century Lutheran Old Church ranks as the largest church in the city.