President-elect Donald Trump will receive the nuclear briefing on Friday morning, hours before he’s inaugurated as the 45th president.

Trump will be given the infamous nuclear codes, and he’ll be instructed in how to launch nuclear attacks that could level cities and wipe out millions of people in a matter of minutes.

“It’s a sobering moment. It defines the ultimate obligation that you might have,” Andrew Card, George W. Bush’s chief of staff who was with Bush on his inauguration day, told Politico.

The codes do not go directly to the US’s missile silos, but are rather used to verify the president’s identity when he gives the order to launch. Once a launch is ordered, it can’t be vetoed.