The following are a few facts about APEC and Pusan:
Members and mission
APEC's 21-member economies account for 57% of world Gross Domestic Product (GDP), 45.8% of world trade volume and 44.8% of the world's population, organisers say.
The APEC member economies are Australia, Brunei, Canada, Chile, China, Hong Kong, Indonesia, Japan, Malaysia, Mexico, New Zealand, Papua New Guinea, Peru, The Philippines, Russia, Singapore, South Korea, Taiwan (under the name Chinese Taipei), Thailand, United States and Vietnam.
Its key policies are to promote trade liberalisation and economic growth in the region.
APEC was founded with 12 members in 1989 as a meeting of ministers in Australia. The APEC leaders' meeting was held for the first time at the 1993 forum in Seattle and nearby Blake Island in Washington state.
Host city Pusan
This year's meeting is being held in South Korea's second city of Pusan, with a population of about 3.7 million. It is the world's fifth largest container port and host of one of the largest film festivals in Asia.
Among the spots the city lists as its most important sites are Beomeosa temple, which was founded in 678, and the UN Memorial Cemetery housing the graves of some of those killed in the UN forces that fought on the South Korean side in the 1950-1953 Korean War.
Tens of thousands of police will be on duty throughout South Korea during APEC. Defences include anti-aircraft missile batteries, a three-tiered naval blockade, a team to battle chemical warfare assaults, subway guards as well as police and soldiers who are highly skilled in the Korean martial art of taekwondo.
A tradition of the meeting is for all participants in APEC to don traditional costumes on the last day. In Pusan, the leaders will wear traditional Korean long coats called durumagi - a V-necked garment that extends to about the knees and is fastened by a bow over the lapel.
At last year's APEC meet in Santiago, the leaders donned brightly coloured ponchos. In Shanghai in 2001, they wore silk jackets,
They have also worn Canadian bomber jackets, Indonesian batik as well as Thai silk shirts and shawls.