In the infamous words of Dr. Evil, the earth is filled with "liquid hot magma." Now, some scientists are looking to drill down into the inner filling of our Earth to do more studying. This is no easy task as the people who have attempted it before will tell you. The price tag will be at least $1 billion USD, with no guarantee of success.
The group of international scientists plan to drill into the mantle in one of three places. The three options are located in the Pacific ocean, along mid-ocean ridge lines where the crust is the thinnest due to the quick forming of said lines. Here, the crust is believed to be as thin as 6km, whereas other parts of Earth have up to an 80km thick crust.
This isn't the first attempt at drilling into the mantle of the Earth. Russia attempted something similar with the Kola Superdeep Borehole, which managed to drill as deep as 12km, though not in the middle of the ocean. "It will be the equivalent of dangling a steel string the width of a human hair in the deep end of a swimming pool and inserting it into a thimble 1/10 mm wide on the bottom, and then drilling a few meters into the foundations."