London International Youth Science Forum

The London International Youth Science Forum is one of the oldest residential science forums in the world. Each year around 500 students aged 16-21 years old attend from 70 countries in London. Students interact with "experts at the top of their fields" in a world-class program of lectures, with access to premier research centers, scientific laboratories and leading educational institutions, including Cambridge and Oxford universities.
Participants at the forum are often winners of national or international scientific competitions, but the conference also emphasises inter-cultural communication through various social events, and in 2016 LIYSF was granted UNESCO patronage.
History.
The idea of a science forum that would bring together top science students from many countries was most evidently considered after World War II, when this idea was realised in the form of student exchanges between different schools and communities in the United Kingdom, the Netherlands, Denmark, and Czechoslovakia. In 1959, writing that "out of like interests the strongest interests grow", Philip Green initiated an co-ordinated programme housing all participants at the University of London.
In the next decades, the conference expanded across the globe, starting from the United States of America to Eastern Asian countries. The initial goal was to "put science into perspective and to encourage those attending to be aware of the needs of the world and what was happening in disciplines other than the one they were studying".
Speakers at LIYSF include world leading scientists and policy makers. 
Reception.
The Forum has received numerous warm receptions. David Cameron, former Prime Minister, described LIYSF as "a fantastic opportunity for young scientists from all over the world to come together... and engage in a programme designed to educate, stimulate and inspire". The Director-General of the United Nations Educational, Scientific and Cultural Organisation, Irina Bokova, notes that LIYSF exhibits commendable understanding of "how science and culture go hand in hand, while sharing knowledge and experiences".
Support.
Support is primarily given by, amongst other organisations and groups, The European Commission, the British Council, Education UK and the GREAT Campaign.