(AP Photo/Paul Newberry)
The worst seats in the Olympic Aquatics Stadium are located behind the huge poles in the four corners of the venue. They offer obstructed views of Michael Phelps, Katie Ledecky, Katinka Hosszu and other stars of the pool.
Rio 2016 organizers sold tickets without warning buyers they wouldn't have a clear view of the action, according to some fans in the affected areas.
Carlos Andrioli of Rio de Janeiro says he paid 500 reals or nearly US$160 for his seats. He didn't get to choose the location, with the ticket system selling the best available seats at the time of purchase. 
"Very disappointing," he said. "It's a one in a lifetime opportunity to see the Olympics. They assign what is supposed to be the best seats available. Who am I going to complain to now?"
Leo Miyakoshi, who lives in Rio, was perched in the second row from the top of the stadium for his only night at the pool. He paid 260 reals or about US$80. 
"I'm quite upset," said Miyakoshi, who planned to move if he spotted an open seat elsewhere. 
Paula Lopes came to the pool with her husband and two boys, ages 8 and 13. They paid 130 reals or about US$40 each for their seats. She said organizers never should have sold the obstructed seats.