This deceptively salty lake looks like blushing pink lemonade.

Bacteria and algae give the salty water its bubblegum hue.

A memorial for public executions that dates back to the 14th century.

This 3,800-year-old site contains markers used to study the movement of the sun and moon and create a lunar calendar.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

This ancient Chinese observatory still contains early astronomy technology.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

A wonderfully kitsch bookstore the size of a supermarket.

This charming, medieval walled village is Spain's first "book town."

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

The spectacular and eerie moss-covered grave site of 19th-century Belgian merchant.

Order cookies baked by cloistered nuns in a 400-year-old monastery.

The largest treasure hoard in Europe is contained in a castle that was bombed out during World War II.

Hidden in the garden of physicist Erwin Schrödinger's house is a life-size figure of a cat from his famous thought experiment.

One of the best-preserved medieval streets in Europe.

At least according to the Guinness World Records.