The Fallout series has got nothing on its mobile sibling Fallout Shelter.

During his 2016 DICE chat this afternoon, Bethesda’s creative director Todd Howard said there have been 4 billion sessions played of the Android and iOS title.

“I think the last stat was 4 billion sessions, making it the most played Fallout game of any Fallout games combined,” said Howard. “We wanted to do something smaller that wasn’t this big three or four year thing and it exploded.

“It brought in an audience you’d never expect.”

Fallout Shelter was released in June 2015 on iOS and it quickly became the number one game on the App Store with 70 million play sessions a day by June 25.

The base builder was released on Android the following August.