This is Dennis Washington’s super yacht, the 225-foot Attessa III.

Found it docked today behind the San Diego Convention Center and got curious about the owner.

Forbes estimates Washington’s fortune at $4.2 billion, most of it held in Montana Rail Link railroad, Montana Resources copper and molybdenum mine—and cash.

His boat, the Attessa, comes with a crew of 15 and accomodates 10, according to Yachtspecs. It’s flying the flag of the Cayman Islands, said to be the world’s leading “super yacht” registry.