When a helicopter discovered a mysterious giant crater on the Yamal Peninsula of Siberia, a place referred to as "the end of the world," speculation was rampant. People suggested it could have been caused by a meteorite, an underground explosion related to nearby natural gas fields, or even something more ominous or extra-terrestrial.

The crater looks almost too incredible to be real, but researchers finally made their way there on July 16 and it most certainly is the real thing. But even though the expedition revealed more information, the exact cause of the crater is still being determined.

Here's what it looks like from a helicopter:

Some think the crater might have been formed by a "pingo" — a geological feature found in areas with permafrost like the Yamal Peninsula.

A pingo is a hill or dome that forms in the permafrost because of an underground ice formation, caused by groundwater forcing its way up towards the surface. There it encounters colder temperatures and freezes. If it melted, due to warming temperatures, it could have left a crater behind.

Another possibility is that as the ground warms, an underground ice formation may have released gas that had been trapped there for thousands of years, which could have forced its way through the surface, bursting out and leaving a giant hole.

Andrei Plekhanov, a senior researcher at the Scientific Research Center of the Arctic, stands at a crater, discovered recently in the Yamal Peninsula, in Yamalo-Nenets Autonomous Okrug, Russia. Russian scientists said Thursday july 17, 2014 that they believe a 60-meter wide crater, discovered recently in far northern Siberia, could be the result of changing temperatures in the region. Andrei Plekhanov said 80 percent of the crater appeared to be made up of ice and that there were no traces of an explosion, eliminating the possibility that a meteorite had struck the region. AP Photo/Associated Press Television "For now we can say for sure that under the influence of internal processes there was an ejection in the permafrost," Andrey Plekhanov, senior researcher at the State Scientific Centre of Arctic Research, told The Siberian Times. In other words, whatever happened caused pressure to build up underground, forcing the above layer of earth — permafrost — to break apart and fly outward from the center of the hole.

Anna Kurchatova from the Sub-Arctic Scientific Research Centre described the process to The Siberian Times as one where frozen gas, salt, and sand underground may have warmed enough to cause "an effect like the popping of a Champagne bottle cork." Russian scientists said Thursday July 17, 2014 that they believe a 60-meter wide crater, discovered recently in far northern Siberia, could be the result of changing temperatures in the region. Andrei Plekhanov, a senior researcher at the Scientific Research Center of the Arctic, traveled on Wednesday to the crater. Plekhanov said 80 percent of the crater appeared to be made up of ice and that there were no traces of an explosion, eliminating the possibility that a meteorite had struck the region. ( AP Photo/Associated Press Television Plekhanov and other researchers have said that the crater was most likely caused by changing temperatures in the region — potentially related to global warming — though more research is needed to be certain. The Yamal Peninsula has experienced particularly warm summers recently, which could have caused the melting.

Russian scientists said Thursday that they believe a 60-meter wide crater, discovered recently in far northern Siberia, could be the result of changing temperatures in the region. Andrei Plekhanov, a senior researcher at the Scientific Research Center of the Arctic, traveled on Wednesday to the crater. Plekhanov said 80 percent of the crater appeared to be made up of ice and that there were no traces of an explosion, eliminating the possibility that a meteorite had struck the region. AP Photo/Press Service of the Yamalo-Nenets Autonomous Okrug Governor The investigation revealed that the hole at the top of the crater has a diameter of approximately 100 feet, smaller than initial estimates of more than 600 feet., though it is tough to measure due to a somewhat oval shape. The crater is deep though — approximately 300 feet, and an icy lake sits at the bottom.

The research team said that ice in the sides of the crater is melting as it's exposed to the sun, causing water to flow down into the lake. This may eventually fill the crater.

Russian scientists said Thursday that they believe a 60-meter wide crater, discovered recently in far northern Siberia, could be the result of changing temperatures in the region. Andrei Plekhanov, a senior researcher at the Scientific Research Center of the Arctic, traveled on Wednesday to the crater. Plekhanov said 80 percent of the crater appeared to be made up of ice and that there were no traces of an explosion, eliminating the possibility that a meteorite had struck the region. AP Photo/Press Service of the Yamalo-Nenets Autonomous Okrug Governor Although researchers thought that at first they'd seen evidence of burning visible on the edges of the crater, the closer examination revealed no traces of a fiery explosion, which rules out a meteorite. Plekhanov also said that the crater isn't quite close enough to the gas fields, about 19 miles away, to have been caused by a gas pumping accident.

The Russian researchers are using satellite footage to see if they can determine when the crater appeared, though they imagine it happened in the past year or two.

Russian scientists said Thursday that they believe a 60-meter wide crater, discovered recently in far northern Siberia, could be the result of changing temperatures in the region. Andrei Plekhanov, a senior researcher at the Scientific Research Center of the Arctic, traveled on Wednesday to the crater. Plekhanov said 80 percent of the crater appeared to be made up of ice and that there were no traces of an explosion, eliminating the possibility that a meteorite had struck the region. AP Photo/Press Service of the Yamalo-Nenets Autonomous Okrug Governor

Plekhanov said that the phenomenon seems natural, though still incredibly strange. He told The Siberian Times, "I've never seen anything like this, even though I have been to Yamal many times."

Here's the original video footage that revealed the crater to the world.