door to hell
This is a 70 meter wide crater in Turkmenistan that has been burning continuously for about 40 years.
In 1971, geologists drilling for gas deposits uncovered a huge underground cavern, which caused the ground over it to collapse, taking down all their equipment and their camp with it. Since the cavern was filled poisonous gas, they dared not go down to retrieve their equipment, and to prevent the gas escaping they ignited it, hoping it would burn itself out in a couple of days. Unfortunately, there was a slight miscalculation as to the amount of gas that was trapped, and the crater continues to burn to this day.
UPDATE: In April 2010, the President of Turkmenistan Gurbanguly Berdimuhamedow visited the site and ordered that the hole should be closed, or other measures be taken to limit its influence on the development of other natural gas fields in the area. [See: wikipedia]
