Rio de Janeiro, Dhu-AlQa'dah 3, 1437, Aug 6, 2016, SPA -- The opening ceremony of the Rio Olympics got underway Friday, with spectators to be taken on a journey through time in the three-hour, low-budget event, dpa reported. Cash-strapped Brazil has had to keep in check spending on its Olympics, the first to be held in a South American city. The opening ceremony will reportedly cost about half of the 42-million-dollar extravaganza in London four years ago. Italian executive producer Marco Balich nevertheless said on the eve of the event that it was "the coolest show I ever produced and worked with." Organizers expected 50,000 people in the audience at the iconic Maracana Stadium, including more than 40 world leaders. The show is built around the concepts of environmental protection, diversity and joy, and will "start in the beginning of life and we wrap up with the future," creative director Andrucha Waddington said. Rio organizers have managed to keep under wraps who will light the Olympic cauldron during the ceremony. Speculation had been high that Brazilian football legend Pele would get the honour, but he announced on Friday that he would not attend due to health reasons. The UOL media outlet reported that former tennis world number one Gustavo Kuerten would be the one to light the Olympic cauldron, as the last of the 12,494 people who have carried the torch since it was lit in April at the birthplace of the ancient games in Olympia, Greece. The Rio Olympics will run through August 21. Many of the 10,500 athletes from 206 countries who will compete in the Games for 306 gold medals were to join the traditional Parade of Nations during the opening ceremony. -- SPA 02:21 LOCAL TIME 23:21 GMT www.spa.gov.sa/w