Kunal Sood, MD on Instagram: "Superfetation is the extremely rare situation where a second pregnancy begins during an ongoing one. Normally, pregnancy blocks this through three layers of protection: ovulation stops, cervical mucus thickens into a plug that prevents sperm from entering, and the uterine lining becomes unreceptive to a new embryo. For another conception to occur, all three of these safeguards would need to be bypassed. Documented human cases are very few, and most involve assisted

Devon Massyn on Instagram: "The craziest dive of my life. We made an expedition to an extremely remote region of the Solomon Islands to film sharks around one of the most active submarine volcanoes on Earth—Kavachi. Because of its isolation, no one had been there in over two years, so we had no idea what we would find or if the volcano was even active at the surface. You are quickly reminded of the intense power of the Earth here. Even while scuba diving more than 50 miles away, we could hear it