What is the RQ-4A Global Hawk US military drone shot down by Iran?

The U.S. says the drone was shot down in an "unprovoked" attack by Iran.

"This was an unprovoked attack on a U.S. surveillance asset in international airspace," Navy Capt. Bill Urban, a U.S. Central Command spokesperson said in a statement.

The RQ-4A Global Hawk is a $120 million surveillance drone which CENTCOM said "provides real-time intelligence, surveillance and reconnaissance missions (ISR) over vast ocean and coastal regions.”

The aircraft has a wingspan on 116.2 ft, nearly the same size of the Boeing 737 Max, and is able to reach altitudes of 65,000 feet.

According to the drone's developer, Northrop Grumman, the drone "flies autonomously at altitudes of more than 60,000 feet, above inclement weather and prevailing winds, for more than 32 hours at a time" and has amassed more than 20,000 flight hours.

The first generation experimental Global Hawks were deployed to the Persian Gulf less than two months after Sept. 11, 2001.

In 2006, the RQ-4A became the first unmanned aircraft system to earn both a military airworthiness certification and a national certificate of authorization to operate in the national airspace, according to Northrop Grumman.

"With this historic accomplishment and more than 35,000 total flight hours, most of that time in combat support over the skies of Iraq and Afghanistan, Global Hawk continues to be a trailblazer in UAS certifications and a pathfinder supporting our men and women overseas in combat," George Guerra, vice president of HALE systems for Northrop Grumman, said in a statement.