National Stadium officially opens roof corridor

National Stadium, also known as the Bird's Nest, officially opened its roof corridor on Saturday for sightseeing and fitness events.

The stadium, which was built for the 2008 Beijing Summer Olympics, opened the roof corridor during an orienteering competition involving by 40 outdoor sports enthusiasts. Orienteering involves individuals or teams racing to navigate a course and visiting set checkpoints in sequence.

Participants started the race cross-country skiing on man-made snow outside the stadium, before competing in a curling contest on artificial rinks inside and running down the roof corridor to complete the 3.8-kilometer course.