Thousands of athletes gather every four years to compete in this international extravaganza that alternates between the Summer Games and the Winter Games. The modern Olympics began just before the 20th century and are a revival of games that originated in Greece. The games include numerous symbols and rituals — notably the torch, the flag and the opening and closing ceremonies. There has been some controversy in recent years over the environmental impact of the Olympics, but the spectacle and athleticism of the Games make it an internationally uniting event. (Photo: Flickr)

What's new at this year's Winter Olympics

Kick-butt alpine skier also happens to be blind

Korea's Olympic ice hockey diplomacy

The list of cities that can host the Winter Games is getting shorter. (Thanks, climate change)

How sustainable will the Winter Olympics be?

A dip in the Seine will soon be possible

Paris proposes $318M facelift for Eiffel Tower

Are we redefining the nature of competition?

13 wild milestones for women in the Olympics

The Rio Olympics, by the numbers

Making the case for a permanent home for the Olympic Games

These U.S. athletes are making history before the Rio Games even begin