Two Mayflowers sit side by side in Plymouth Harbor — one is a reproduction of the original, the other a version for the 21st century.
"I think it's really cool," said Plymouth resident Deanne Smith. "I wanted to swing by just to see it."
The high-tech vessel is called the Mayflower Autonomous Ship, and it set sail in April from Plymouth, England, attempting to retrace the path of the original Mayflower from 400 years ago.
But this one had nobody on board.
"It's a trimaran," said Michele Pecoraro. "It weighs 5 tons, and that little guy made it all the way across the Atlantic Ocean."
The solar-powered ship is driven by artificial intelligence and created by IBM and Promare, a marine research nonprofit.
Its purpose is to collect data for research projects on numerous topics like marine life and pollution caused by plastics, and for scientists to learn more about AI.
"It's definitely a step forward for AI," said Pecoraro, business development manager for Promare. "The technology in this is cutting edge."
The unmanned vessel is on its own at sea, but hundreds of people on land are watching every move.
"The AI captain makes the decisions," said Pecoraro. "There's always the human backup of the command center."
It's believed to be the largest autonomous vessel to cross the Atlantic, and it's already an attraction drawing people on the water and on land to take pictures.
"It's just amazing from 400 years to today what's happened with technology," said Plymouth resident Marianne Geuss.
It took longer than expected for the ship to arrive.
There were weather issues and mechanical problems, so the ship had to make pit stops in Portugal and Canada before pulling into Plymouth Harbor on Thursday.