Moonwalker Buzz Aldrin marked the 50th anniversary of humanity’s first moon landing at the Apollo 11 launch site.
Mr Aldrin accompanied US vice president Mike Pence to Florida’s Kennedy Space Centre on Saturday and showed him the pad where he began that momentous journey 50 years ago.
Mr Aldrin was later given a standing ovation during a speech by Mr Pence.
Mission commander Neil Armstrong, the first man to step on to the moon on July 20, 1969, died seven years ago.
Command module pilot Michael Collins did not attend the Florida celebration.
Mr Pence said Apollo 11 was the only event of the 20th century that “stands a chance of being widely remembered in the 30th century”.
He reiterated the Trump administration’s push to put Americans back on the moon by 2024.
The golden anniversary is being celebrated at events across the US.
At the Kennedy Space Centre cars were backed up for miles Saturday outside the visitor complex.
In Armstrong’s home town of Wapakoneta, Ohio, runners competed in Run to the Moon races.