South Korea maintains diplomatic relations with 191 countries. The country has also been a member of the United Nations since 1991, when it became a member state at the same time as North Korea. South Korea has also hosted major international events such as the 1988 Summer Olympics and 2002 World Cup Football Tournament (2002 FIFA World Cup co-hosted with Japan) and the 2011 IAAF World Championships Daegu South Korea. Furthermore, South Korea had hosted the 2018 Winter Olympics which took place in Pyeongchang, South Korea from 9 to 25 February. South Korea is a member of the United Nations, WTO, OECD/DAC, ASEAN Plus Three, East Asia Summit (EAS), and G-20. It is also a founding member of Asia-Pacific Economic Cooperation (APEC) and the East Asia Summit. On January 1, 2007, South Korean Foreign Minister Ban Ki-moon assumed the post of UN Secretary-General, serving in that post until December 31, 2016. North Korea Inter-Korean relations may be divided into five periods. The first stage was between 1972 and 1973; the second stage was Pyongyang North Korea's delivery of relief goods to South Korea after a typhoon caused devastating floods in 1984 and the third stage was the exchange of home visits and performing artists in 1985. The fourth stage, activated by Nordpolitik under Roh, was represented by expanding public and private contacts between the two Koreas. The fifth stage was improved following the 1997 election of Kim Dae-jung. His "Sunshine Policy" of engagement with North Korea set the stage for the historic June 2000 Inter-Korean summit. The possibility of Korean reunification has remained a prominent topic. However, no peace treaty has yet been signed with the North. In June 2000, a historic first North Korea-South Korea summit took place, part of the South Korea's continuing Sunshine Policy of engagement. Since then, regular contacts have led to a cautious thaw. President Kim was awarded the Nobel Peace Prize in 2000 for the policy. With that policy, continued by the following administration of president Roh Moo-hyun, economic ties between the two countries have increased, humanitarian aid has been sent to North Korea and some divided families have been briefly reunited. Military ties remain fraught with tension, however, and in 2002 a brief naval skirmish left four South Korean sailors dead, leaving the future of the Sunshine policy uncertain. The North Korea cut off talks but the South remained committed to the policy