Typically this question would show up as an essay question in an exam. To start (introduction), the case study of choice must be highlighted, with a brief insight into who is responsible for choosing the venue. I've chosen the 2012 London Olympics, and the International Olympic Committee are responsible for selecting the host country for the event.Next, the body of the essay would be made up of the various contributing factors – and in Geography, it's always important to look at social, economic, environmental, and political factors (or those of which are relevant to your question!). Below I've added a few points within each factor for this specific case study:Social: The UK has a tradition of sport (eg. Lord's cricket ground, Wimbledon for tennis, Twinkenham for rugby)Large carrying capacity: 2m fans visited the 2012 games//1,500 hotels in LondonRegenerate lower income areas, and the sports infrastructure can be used for future use in the communityEconomic:Pre-existing sports infrastructure would save costs40% of the world's equities are traded in London = attractive for sponsorships for the eventEnvironmental:Thames Flood Barrier: prevent floods during the eventJune-July tends to have good weatherClose to European countries (more spectators!)Prior to the conclusion, examiners like to look out for a "but..." (that critical thinking) so it would be good to talk about how choosing London may have prevented Istanbul/Havana from having the chance to develop, how London is the 6th most expensive city in Europe (2016), or how the games caused lots of smaller businesses to relocate.