Tsukiji Fish Market

The world's largest, busiest fish market has long been a favorite destination for jet-lagged tourists with predawn hours to fill. But the main reason for going at 5 a.m. is to catch the live tuna auctions. Before you go, however, be sure to check this website to see if public access is permitted that day. If so, it will be on a first-come, first-serve basis, and limited to 120 people, admitted in two shifts of 60. You can register starting at 4:30 a.m. at the fish information center inside the Kachidoki Gate off Harumi Street. If you prefer to do your exploring at a more reasonable hour, keep in mind that by 9 a.m., business will have already started to wind down. You'll still see fishmongers filleting the day's catch, but you won't have to dodge so many trucks and trolleys.