Meteora Rock Pillars, Greece

Meteora rises above the plain of Thessaly in central Greece, a cluster of sandstone and conglomerate pillars that tower over the town of Kalabaka below. The rock formation was shaped over millions of years as an ancient river delta was uplifted and then carved by wind, water, and seismic activity into the smooth, steep-sided towers seen today. Its name comes from the Greek word for "suspended in the air," a fitting description for the monastery buildings that sit on several of the summits.

Orthodox monks began settling the pillars in the 14th century, drawn to the isolation and natural defense the rock towers offered during a turbulent period in the region's history. Reaching the monasteries once meant climbing removable wooden ladders or being hauled up in nets and baskets on a rope and windlass; steps cut into the rock later made the climb easier. Of the roughly two dozen monasteries once active here, a handful remain in use today, and the site is recognized by UNESCO as a World Heritage Site for both its geology and its monastic architecture.

In this puzzle, the warm stone walls and terracotta roofline of the monastery give a solid block of flat color and straight edges to assemble first, while the layered, shadowed rock face behind it rewards slower work matching texture and tone. The hazy ridgeline in the background fills in last, once the sharper foreground shapes are in place.