An investigation is underway into the Delta plane that crash-landed Monday in Toronto. What caused it remains to be seen, but here's what we know so far.

Investigators are looking into how all 76 passengers and four crew members aboard Delta Air Lines Flight 4819 survived after the plane crash-landed in Toronto on Monday.

Delta Flight 4819, which was arriving in Toronto from Minneapolis, burst into flames upon landing and flipped upside down on the runway Monday.