Today is Pi Day, for obvious reasons. Pi is a Greek letter representing the ratio of a circle's circumference to its diameter, a mathematical constant. If a circle's diameter is one, its circumference is approximately Happy Pi day.

the-world-today: “ Derweze, also known as the door to hell, is a 70 meter wide hole in the middle of the Karakum desert in Turkmenistan. The hole was formed in 1971 when a team of soviet geologists.