In case you haven't heard, a trio of strange sinkholes or craters have recently been discovered in northern Russia. So far the holes have the international scientific community baffled, partly because the holes are so remote that just getting to them in order to study them poses a real challenge. But certain journalists and researchers have journeyed to the holes, and consequently there are a lot of photos of three sites now circulating online and across social media. We've gathered the five best photos we could find of the mysterious Siberian craters. Check them out below:

According to the Daily Mail, the original crater (pictured here), was discovered by helicopter pilots flying over the region near Bovanenkov. This is the largest of the three craters, though no one has measured exactly how large or deep it actually is. 

This is the second crater or sinkhole discovered recently, and it is found on the Yamal Peninsula close to the village of Antipayuta. It is reported to have a diameter of 49 feet. Local residents claim that the crater formed on September 27th, 2013. 

This is the third crater discovered recently, and it is on the Taymyr Peninsula. It was apparently discovered by reindeer herders who came very close to falling in to the massive hole. Locals claim the crater is actually a perfect cone with a depth of 200 to 330 feet. It's diameter is said to be around 13 feet. 

While no one is certain what caused the formation of these mysterious craters, some scientists have postulated that a buildup of methane gases beneath the surface of these regions exploded to due to rapid atmospheric warming and other effects of climate change. 

Of course, other theories are also spreading rapidly across the internet. Everything from meteors, to UFOs exploding into or out of the ground, to secret government satellite weapons are being thrown about online as possible causes of these mysterious holes. 
All we can say for sure is that this is all really weird.