The spectacular, 8km Yagodina Cave is the longest known Rodopi cave and, with its many abysses and labyrinthine tunnels, also one of Bulgaria’s deepest. The 45-minute tour highlights the remarkable stalagmites and stalactites, which resemble curtains, and mentions the Neolithic settlers who lived here 8000 years ago. Visitor numbers permitting, tours leave on the hour every hour between 9am and 4pm, except at midday. From 1 October to 1 May, at least six visitors are required for the tour; otherwise, you pay 15 lv. In summer, 10 visitors (or 25 lv) are required. Remember that no matter how hot it may be, caves are chilly, so pack extra clothes.