This massive memorial commemorates those who died in the Manchester Arena bombing.

The city of Manchester quietly unveiled this tribute to a 19th-century massacre.

This London marker celebrates the spot where the world-famous English band was founded.

Once one of the largest rooms full of books in the world, this bookstore basement is still a treat for bibliophiles.

The chaotic studio of one of the 20th century's most important artists has been preserved down to the dust.

Remnants of a 4th-century church with vivid medieval frescoes and ancient sarcophagi hide beneath this old basilica.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

Commonly acknowledged as the only public monument to the Devil himself.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

The remains of the second-oldest zoo in Europe can be seen within these library gardens.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

This lucky bronze frog was gifted to Madrid by a casino.

The only urban monument in the world designed by the great surrealist painter Salvador Dalí.

Madrid's last horchata kiosk is a blue-and-white beacon of refreshment.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

Just like in Hollywood, Madrid has also a forgotten walk of fame.

This fascinating and poignant museum chronicles every imaginable aspect of Spanish colonialism in the Americas.

An ancient Egyptian temple in the middle of Madrid, Spain.

The lengthy skeleton of one of the tallest Spaniards of all time is on display in Madrid.

A whimsical brother of the nearby Fallen Angel statue takes the falling part quite literally.

For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

The famous polar explorer stands outside the Royal Geographical Society's headquarters.