Irish sprinter Jason Smyth aims to emphasise his status as the world's fastest Paralympian when he races in a 100m event in Rio on Monday.
A year before the start of the 2016 Paralympics in Rio, the city is staging 100m races with top sprinters from various Paralympic categories.
Four-time Paralympic gold medallist Smyth's opponents include Australian world record holder Evan O'Hanlon.
"I feel privileged to be in Rio," said Smyth, 28.
"It truly is unique to have the best in the world from various disabilities come together in one race.
"It is such a great way to mark a year to go until the start of the greatest sporting event on earth," added visually impaired athlete Smyth, who now competes in the T12 category.
Smyth suffers from the degenerative condition Stargardt disease, which limits his vision to the outlines of shapes.
The men's field in Rio will include amputees Richard Browne (USA) and Petrucio Fereira (Brazil), plus the visually impaired David Brown (USA) and Felipe Gomes (Brazil).
O'Hanlon, who competes in the T38 cerebral palsy class, has a 100m personal best of 10.79 which is a world record in the category.
Smyth's 100m personal best in Paralympic competition is 10.46, although he ran a time of 10.22 at an able-bodied meeting in 2011.
World and Paralympic silver medallist Browne previously held the T44 single below-leg amputee class 100m record and has a personal best of 10.75.
The sprint races are taking place as part of a Paralympic Festival at the Rodrigo de Freitas Lagoon in the southern part of Rio.
Smyth's main target for this year is the IPC World Championships which take place in Doha from 21-31 October.