The 20th Association of Southeast Asian Nations (ASEAN) Summit opened Tuesday during which the leaders from the member states will discuss issues concerning ASEAN community building and strengthening regional connectivity, and adopt a series of documents and agreements.

The following is a brief introduction to previous ASEAN summits and main achievements at the meetings.

The 1st ASEAN Summit was held in Bali, Indonesia, in February 1976. The leaders of ASEAN member countries endorsed the Treaty of Amity and Cooperation in Southeast Asia and the Declaration of ASEAN Concord.

The 2nd ASEAN Summit was in Kuala Lumpur, capital of Malaysia, in August 1977, at which a joint communique was signed.

The 3rd ASEAN Summit was held in Manila, the Philippines, in December 1987. The summit approved the Manila Declaration 1987 and four major economic agreements aimed at promoting economic cooperation within the organization.

The 4th ASEAN Summit was in Singapore in January 1992. The leaders of ASEAN member countries signed the Singapore Declaration and a framework agreement on enhancing ASEAN economic cooperation. They decided to hold a summit every three years.

The 5th ASEAN Summit was held in Bangkok, Thailand, in December 1995, during which the Bangkok Declaration was adopted. The leaders of the ASEAN member countries signed a number of important documents with the aim of promoting mutual economic and political cooperation. They also agreed to have informal meetings every year.

The 6th ASEAN Summit was in Hanoi, Vietnam, in December 1998. The leaders of ASEAN member countries approved the Hanoi Declaration, the Hanoi Plan of Action and a number of what they called "bold measures" to strengthen economic, political and security cooperation.

The 7th ASEAN Summit was held in Bandar Seri Begawan, capital of Brunei, in November 2001. The leaders of the ASEAN member countries endorsed the Mid-Term Review of the Hanoi Plan of Action, and identified new priorities which included ASEAN integration, information and communications technology along with human capacity building. The leaders also adopted a 2001 ASEAN Declaration on Joint Action to Counter Terrorism and a Declaration on HIV/AIDS.

The 8th ASEAN Summit was held in Phnom Penh, Cambodia, in November 2002. The leaders of the ASEAN nations discussed and reached a consensus on regional and international issues of common concern, which included ASEAN integration and the fight against terrorism. They signed the ASEAN Tourism Agreement.

The 9th ASEAN Summit was in Bali, Indonesia, in October 2003, highlighting increased mutual trust and cooperation among the group's member countries and its dialogue partners. The summit, which is seen as "very productive," adopted a milestone document, the Declaration of ASEAN Concord II, also known as Bali Concord II, which envisions the establishment of an ASEAN Community by 2020.

The 10th ASEAN Summit was held in Vientiane, Laos, in November 2004, at which the leaders of the ASEAN nations adopted the Vientiane Action Program, a vehicle to build an ASEAN community through realizing comprehensive integration.

The 11th ASEAN Summit was in Kuala Lumpur, Malaysia, in October 2005. The meeting adopted the Kuala Lumpur Declaration on the establishment of the ASEAN Charter.

The 12th ASEAN Summit was held in Cebu, the Philippines, in January 2007. The leaders of the ASEAN nations endorsed the Cebu Declaration on the blueprint of the ASEAN Chart to form the basis of a mini-constitution that seeks to transform the ASEAN into a legal entity with binding rules and regulations.

At the 13th ASEAN Summit in Singapore in November 2007, ASEAN leaders signed the ASEAN Charter and The Declaration on the ASEAN Economic Community Blueprint.

At the 14th ASEAN Summit in February 2009, ASEAN leaders signed the Cha-am Hua Hin Declaration on the Roadmap for an ASEAN Community (2009-2015). They also adopted a number of important documents that are of strategic importance to the ASEAN development.

ASEAN leaders at the 15th ASEAN Summit in October 2009 adopted the Cha-am Hua Hin Declaration on the Inauguration of the ASEAN Intergovernmental Commission on Human Rights (AICHR), Cha-am Hua Hin Declaration on Strengthening Cooperation on Education to Achieve an ASEAN Caring and Sharing Community, and Draft ASEAN Joint Statement on Climate Change.

The 16th ASEAN Summit, held in Hanoi, Vietnam in April 2010, focused on measures to enhance solidarity and cooperation within the group and to deepen ASEAN's ties with partners. Leaders pledged to effectively implement the bloc's cooperation pacts over the next five years.

In October 2010, leaders attending the 17th ASEAN Summit in Vietnam adopted several key documents on strengthening connectivity within the bloc, on the improvement of human resources development and also on the protection of women and children.

The leaders of the 10 member states of the regional bloc agreed and adopted at the 18th ASEAN Summit held in May 2011 in the capital of Indonesia three joint statements on "ASEAN Community in a Global Community of Nations", "Establishment of the ASEAN Institute for Peace and Reconciliation" and "Enhancing cooperation against trafficking in persons in Southeast Asia".

At the 19th ASEAN Summit held in Bali, Indonesia in November 2011, the ASEAN leaders adopted the Bali Declaration on ASEAN Community in a Global Community of Nations, or the Bali Concord III, Agreement of the Establishment of the ASEAN Coordinating Center for Humanitarian Assistance on Disaster Management, and the ASEAN Declaration on Unity in Diversity: Towards Strengthening the ASEAN Community.

The ASEAN groups Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam.