How Eratosthenes calculated the Earth’s circumference more than 2k years ago?

In 240 BC, the Greek astronomer, geographer, mathematician, music theorist, and librarian Eratosthenes of Cyrene (c. 276 BC – c. 195/194 BC) calculated the circumference of the Earth without even leaving Egypt. Here’s how:

8 famous places to see before they have vanished

There are a lot of natural and human-made wonders in the world. But everything has an end, and sooner or later, they’ll be gone. Unfortunately, some of them will be vanished sooner, even in a few decades. Here are eight famous places to see before they have vanished, just in case you may want to …

Drones Sacrificed for this Spectacular Volcano Video

A spectacular video (drones sacrificed while shooting it!) from the National Geographic: explorer Sam Cossman operated camera-mounted drones to capture high-definition images of the Marum (also spelled Maroum) crater in Ambrym, Vanuatu. Vanuatu is a Pacific island nation located in the South Pacific Ocean.

Amazing Earth photos from ISS

The Expedition 49 Notes 1 (the 49th expedition to the International Space Station) crew members (Anatoli Ivanishin, Kathleen Rubins and Takuya Onishi) has taken amazing photos of Earth from ISS. Four of them have been published on the ISS Facebook page. They are really, really beautiful and awe-inspiring!

Okavango Delta, Botswana

The Okavango Delta is a unique pulsing wetland where the 1,600 km (990 mi) long Okavango River reaches a tectonic trough in the middle of the Kalahari Desert in northern Botswana. Each year approximately 11 cubic kilometers of water spread over the 6,000-15,000 km2 area. It is on the UNESCO World Heritage List as well …

Slope Point, New Zealand

“Slope Point” is the southernmost point of New Zealand’s South Island. It lies 4803 km (2984 mi) from the South Pole and 5140 km (3194 mi) from the equator. It offers spectacular views of the surrounding ocean and coastline. The place is regularly exposed to extreme weather conditions including heavy winds. The fierce and cold …

Dragon Hole: World’s deepest “blue hole”

The world’s deepest “blue hole” has been discovered in the South China Sea, and it is named “Dragon Hole”. With the depth of 300.89 meters (987.2 feet), it surpassed the Dean’s Blue Hole in the Bahamas, which is 202 meters (663 feet) deep. For comparison, the Eiffel tower is 324 meters (1,063 feet) tall, so …

10 Strange Places on Earth

The Earth, our home has a lot of beautiful, amazing locations – and some strange places as well. These weird places sometimes look “impossible”, sometimes dangerous, sometimes scary, but despite all that, still can be beautiful. Here are ten of them.