View Photo Gallery: A look at the buildup to the Summer Games, which kick off July 27 in London.

Opening ceremonies for the Summer Olympics will take place six months from today in London’s Olympic Stadium. As London organizers enter the stretch run of preparations for the Games, read about the biggest challenges they face here.

Security, transportation and spending head the list of concerns. Meantime, enthusiasm among the British public has yet to reach a fever pitch; a recent poll showed just 32 percent of residents were excited to be hosting the Games.