Today’s Wonder of the Day was inspired by Raina. Raina Wonders, “What are the seven wonders of the world and how did they become one of the seven wonders?” Thanks for WONDERing with us, Raina!

If aliens visited Earth, what marvels of human art and architecture do you think they'd be most impressed with? Would it be tall skyscrapers, like the Empire State Building? Or would they prefer an interesting monument like the Eiffel Tower or the Leaning Tower of Pisa?

Modern humans are certainly good at building impressive structures, but did you realize that ancient humans had their own accomplishments to be proud of? Long ago, seven of these impressive feats of art and architecture came to be known as the Seven Wonders of the World.

Today, we refer to them as the Seven Wonders of the Ancient World to distinguish them from modern marvels. Let's learn a bit about each of these ancient wonders.

The most famous of the ancient wonders — and the only one still in existence — is the set of Great Pyramids located at Giza in Egypt. Built between 2,700 B.C. and 2,500 B.C. without the help of modern machines or tools, the largest of the pyramids, Khufu, reigned as the tallest building in the world for more than 4,000 years.

The Hanging Gardens of Babylon were supposedly built by a Babylonian king around 600 B.C. near the Euphrates River in what is now Iraq. Planted more than 75 feet in the air, the gardens were spread over a large square brick terrace with many steps supported by tall stone columns. Despite being mentioned in both Greek and Roman literature, scholars now believe the Hanging Gardens of Babylon probably never existed.

The Statue of Zeus at Olympia filled the god of thunder's temple at the original site of the ancient Olympics. It was approximately 40 feet tall and covered in gold and ivory. This famous statue remained in the temple for more than 800 years until the temple was closed. Scholars believe it was destroyed in a fire in Constantinople in 462 A.D.

The Temple of Artemis at Ephesus was actually a series of temples and altars that were built, destroyed, and rebuilt multiple times on the same site on the west coast of what is now Turkey. These marble temples were decorated by some of the best artists of the ancient world. The last temple was destroyed around 262 A.D., and archeologists discovered remains of some of the temple's columns in the 1860s.

The Mausoleum at Halicarnassus was located in what is now southeastern Turkey. Built in 353 B.C., the tomb was approximately 135 feet tall and built entirely of white marble. It consisted of a base of steps topped by columns that supported a pyramid-shaped roof. Destroyed by an earthquake in the 13th century, the remains of the mausoleum were later used to fortify a castle.

The Colossus of Rhodes was the tallest statue of the ancient world. The huge bronze sculpture of the sun god Helios stood over 100 feet tall and was completed in 280 B.C. It stood for 60 years before being destroyed by an earthquake. Hundreds of years later, Arab invaders allegedly sold the remains of the statue as scrap metal.

The Lighthouse of Alexandria was completed around 270 B.C. Situated on the island of Pharos near Alexandria, the lighthouse used mirrors to reflect sunlight to guide ships traveling the Nile River in and out of the busy harbor. Once standing nearly 400 feet tall, the statue was eventually destroyed by a series of earthquakes from 956 A.D. to 1323 A.D. Archeologists have found some of its remains at the bottom of the Nile.

If you had to name a modern Seven Wonders of the World, what examples of human art and architecture would you choose? Given that only one of the Seven Wonders of the Ancient World remains, what factors would guide your choice of modern wonders?

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