Hike, spa-hop, and find Europe’s hottest springs “Bulgaria is among the countries richest in mineral waters in Europe,” says ...

Where to stay in Sofia, Bulgaria. ... 400 rooms, 10 restaurants and bars, a spa and swimming pool, the Grand Hotel Millennium is about as big and bold as a hotel can be in Sofia.

Hisar boasts a formidable collection — hundreds of kidney-, bladder- and gallstones which have been expelled after treatment with water from the 22 mineral springs in the region.