The Leaning Tower of Pisa is one of Italy’s (and the world’s) most recognisable landmarks—but the tilt that made it famous wasn’t part of the plan. Construction started in the 12th century, and the soft ground caused it to lean almost from the beginning. Up close, it’s oddly striking, almost like a lopsided wedding cake, and yes, you can still climb it.

The Pasha Gardens is a little-known gem near the old town of Thessaloniki. Half-demolished whimsical ruins are spread across the garden, granting it an air of mystery. It is no surprise that numerous myths and fables have stemmed from here. The park's imaginative, Gaudí-esque architecture centres around an ornate fountain encircled by a tunnel leading nowhere.

You have the unique opportunity to watch one of nature's most powerful, beautiful processes as the earth unfurls to release its magma from the volcanoes. As one of the most active volcanoes on the planet, Kīlauea volcano is consistently one of Big Island's biggest attractions. Its reputation precedes it as a sacred place for Native Hawaiians as well. Marvel at the active Mauna Loa, learn about volcanology at the Jaggar Museum, take a selfie at the viewpoint overlooking the Halema'uma'u Crater. The long, underground cave formed by ancient flowing lava called the Thurston Lava Tube (Nāhuku) is another must-see.