2. Portions of the Great Wall of China, China

The Great Wall of China is considered one of the New Seven Wonders of the World, and for good reason. With fortifications spanning a distance of 21,196.18 km (13,170.70 mi) in total, the wall stretches along the northern borders of China and is considered one of the most impressive architectural accomplishments in history.

However, while you still visit some of it, other parts have long crumbled away or have been damaged by people. It’s not too much of a surprise, given some of the oldest parts have been dated as far back as the 7th century BCE. If you want to see what remains, now may be your chance, as time is catching up to it.