Today we made an attempt to visit the Shanghai World Expo 2010, the problem was so did the rest of China!
I have never seen so many people in one place and although the buildings looked great and the general organisation was superb the actual experience was awful due to the large crowds.
Many of the popular pavillions had queuing times in excess of 5 hours and even some of the less popular ones had relatively long queue times for nothing special. After giving up all hope of visiting the Chinese and Japanese pavillion, we queued for 45 minutes to visit the Turkmenistanian(????) pavilion only to see a few rugs, some jewelry and a brief presentation on their communication infrastructure.
Maybe my expectations were too high but I am glad I didn't travel to Shanghai specifically to see the Expo, unlike the thousands of others that visited with me today!