The Asia-Pacific Economic Cooperation summits, which draw the U.S. president and 20 other regional leaders, are sometimes memorable for just one moment: the leaders posing for a group photo in unexpected attire.

Former President Bill Clinton started the tradition in 1993, when he handed out leather bomber jackets similar to those worn by American fighter pilots. The U.S. leader apparently wanted his fellow VIPs to feel relaxed at the meetings.

Dubbed the "silly shirts" photo by some, the occasionally awkward ceremony became a signature event at most annual APEC gatherings, elevating native garb of the host countries to a brief moment of world fame.

The 21 APEC leaders have posed for together in batik shirts (Malaysia in 1998), Chinese jackets (Shanghai 2001), flowing ponchos (Chile 2004) and in Vietnamese "ao dai" — elegant silken tunics in which several of the leaders were visibly ill at ease — in 2006.

The tradition had a three-year hiatus — in Yokohama, Japan, in 2010, Hawaii in 2011 and Vladivostok, Russia, in 2012 — when the leaders donned regular Western business attire.

Then Indonesia and China revived the group photo in traditional garb at the last two APEC summits.

The Philippines' barong tagalog, a partially see-through shirt sewn from pineapple fiber and silk that was used at the 1996 summit, may have a re-run when Manila hosts APEC this week.