Greece: Meteora
Meteora is otherworldly – over 20 active Greek Orthodox monasteries built high into the monolith cliffs and rock pillars of a surreal landscape. Six of the monasteries are accessible (“accessible”by descending to the bottom of the pillar the monastery is on and then ascending all the way up, so quite a hike). Great Meteoro is the largest and most visited monastery, Holy Trinity is the hardest to get to (located on top of a single isolated pillar), and St Stephens affords superb views into the valley. The entire Meteora and the valleys below is an incredible place and an absolute “must see before you die”. Naturally, this is on UNESCO list.