In this Tuesday, Oct. 15, 2019 photo, a Shiite Muslim cleric walks past anti-U.S. graffiti on the wall of the former U.S. Embassy, in Tehran, Iran. For those who were there, the memories are still fresh 40 years after one of the defining events of Iran's 1979 Islamic Revolution, when protesters seized the U.S. Embassy in Tehran and set off a 444-day hostage crisis whose consequences continue to reverberate to this day. (AP Photo/Vahid Salemi)