Malaysian Prime Minister Najib Razak announced Wednesday* that experts have "confirmed" that the Boeing 777 part found on Reunion Island in the Indian Ocean is wreckage from Malaysia Airlines Flight 370; a French official called the belief that the debris is from MH370 a "strong supposition" and said that further analysis will be performed. Reunion Island is a French possession, and the debris had been sent to a lab near Toulouse for analysis.
MH370 disappeared on March 8, 2014, and is thought to have crashed in the Indian Ocean somewhere west of Australia, but a large-scale search in that area has to this date not found any remnants of the plane. Reunion Island is roughly 3,000 miles from the search area, but it is believed that "wind, waves, and ocean currents" could have washed the recently discovered debris from one location to the other.
The cause of the crash is still unknown, and there is no evidence that the plane was brought down intentionally.
*Thursday in Malaysia's time zone.