Using NASA's data, an atmospheric river (AR), named AR Dena, was found responsible for the record floods of March 2019 in Iran. This rare AR started its long, 9000 km journey from the Atlantic Ocean and travelled across North Africa before its final landfall over the Zagros Mountains. Water transport by AR Dena was equivalent to more than 150 times the aggregated flow of the four major rivers in the region (Tigris, Euphrates, Karun and Karkheh). This event was a compelling example of rapid dry-to-wet transitions and intensification of extremes, resulting from the climate change.