Stonehenge was constructed in six phases approximately 3000 and 1520 BCE, in the passage from the Neolithic Period (New Stone Age) to the Bronze Age. It is notable as a prehistoric stone circle for its intentionally carved sarsen stones (blocks of Cenozoic silcrete) set in post-and-lintel arrangement, as well as the remote provenance of its smaller bluestones (igneous and other rocks) from 100–150 miles (160–240 km) away, in South Wales. The monument’s name is most likely derived from the Saxon stan-hengen, which means “stone hanging” or “gallows.” Stonehenge was named a UNESCO World Heritage site in 1986, along with more than 350 surrounding antiquities and megaliths (ancient earthworks consisting of a circular bank and ditch), along with the similar temple complex at Avebury.

At the end of the 13th century, the inhabitants of Florence desired to construct a cathedral that mirrored their city’s rising status. Work continued for more than a century under the supervision of several great architects, including Giotto and Pisano, until by 1420, Filippo Brunelleschi was prepared to crown it with the dome–a thrilling architecture and design feat for its day and one that continues to astound architects today for its daring.

The Duomo, Italy’s third-largest church, soars above the old town and is more than 152 meters long and 90 meters broad at the cathedral (where the two major aisles intersect). But it’s the craftsmanship, not the magnitude, that makes this cathedral of Europe’s must-see attractions. With a spectacular display of inlaid marble in red, white, and green, the magnificent façade, constructed in the 1800s to replace an incomplete one demolished three decades earlier, dominates Piazza del Duomo.