Discovering the mountains, lakes and cultural capitals of Bulgaria is like unearthing a secret treasure trove. The UNESCO sites of Rila Monastery, the Thracian tombs of Kazanlak and Sveshtari, and Pirin National Park add to the adventure of exploring in the far reaches of Eastern Europe. The capital, Sofia, has long been renowned for its leafy charms with parks and gardens adding to the enchantment of the Alexander Nevsky Cathedral and high-end retail therapy along Vitosha Boulevard.