Scientists suspect the Nasca lines are over two millennia old. They depict over 300 geometric shapes and 70 figures of animals, including a spider, monkey, and hummingbird. Image Credit: Stock photo/Pixabay

There are so many spectacular sights around the Earth, but many of them defy the technological capabilities of the time. So much so that some have even suggested they were built by aliens, according to an October 2017 report in the National Geographic.

Click start to play today’s Crossword, where you’ll have to ‘think’ again about how you perceive certain things, in the clue for 10-Across.

Some of humanity’s most impressive achievements boggle the mind, because historians and researchers are not able to piece together how prehistoric civilisations managed to build such large, enigmatic structures.

Here are a few to note:

1. Sacsayhuaman

Sacsayhuaman Image Credit: Unsplash/Ruben Hanssen

In the Peruvian Andes, lies a fortress called Sacsayhuaman, which is built from gigantic stones stacked together like a jigsaw puzzle. Constructed over 1,000 years ago, the fortress walls are made of rocks weighing about 360 tonnes each, and carried for more than 32km before being lifted and inserted into their proper positions with incredible precision. It’s a feat of engineering that left people wondering how the Incas did it. The answer was found recently, when archaeologists uncovered traces of a rope and lever contraption that the Incans used to transport stones from quarries to cities.

2. Nasca lines

On a plateau in the Peruvian desert, 321km southeast of Lima, there exist more than 800 long, straight white lines. At first glance, they appear random, but go further and over 300 geometric shapes and 70 figures of animals are revealed. The biggest of the shapes stretch nearly 1,200 feet across and are best seen with an aerial view – something the civilisation would not have been able to do. Scientists suspect the Nasca lines are over two millennia old. Nobody knows exactly why the lines were made – initially, they were suspected to depict constellations, but more recently, researchers have found evidence to show the Nasca lines could have been ceremonial or ritualistic.

3. Face on Mars

Face on Mars
Face on Mars Image Credit: Wikimedia Commons/Viking 1, NASA

First spotted by the Viking 1 orbiter in 1976, the face on Mars looks like a human face, and is nearly 3.21km long. It lies in the Cydonia region of Mars, and was once thought to just be a result of shadow play. But when US space agency National Aeronautics and Space Administration’s (Nasa) Mars Global Surveyor took a much higher resolution picture, in 2001, they found no face at all. The elusive face turned out to be a Martian mesa, like a flat-topped hill you’d find on Earth. No alien interference there!

What do you think of such intriguing places? Play today’s Crossword and let us know at