Continuous positive airway pressure (CPAP) machines are used to maintain an open airway in patients diagnosed with obstructive sleep apnea. The machine functions by blowing pressurized air into the airway via mask at a setting determined by sleep study and prescribed by a physician.
Also the second largest impact structure on Earth, the 1.85 billion years old Sudbury crater in Canada, hosts world-class mineral deposits - in this case nickel-rich minerals that were melted and concentrated by the extreme heating caused by the impact.
For the lake of the same name in Oregon, see Crater Lake. Not to be confused with lava lakes, a rare phenomenon where a volcanic crater can sustainably contain a significant volume of molten lava. Landsat image of Lake Toba, Indonesia, the largest volcanic crater lake in the world.