If there were any place that can make you realize just how important air conditioning is, it would be the Vatican and the Sistine Chapel. The chapel that receives over six million tourists a year happens to have a problem with all the visitors that pass through the halls of it and the Vatican museum. The Sistine Chapel was running into problems with pollutants that were being brought in or left around the chapel by the visitors, and that meant two things for the Sistine chapel. Either the Vatican could limit the amount of people who could see the chapel, or they could upgrade their technology around the chapel.
The Vatican decided to do both. They decided to limit the Sistine Chapel to 2,000 Visitors at any one time, and 20,000 a day. This is more than the amount they expect to see at the chapel, but it gives them a limit for future problems of more and more people having resources to travel the distance to the Vatican. Additionally they upgraded with a number of electronics, including goggles that are similar to google glass, which will provide a 3d expanse of the tour through the Vatican museum and Sistine Chapel. It also includes LED lights being installed, and an entirely new air conditioning system to handle all the people that are moving through the chapel and causing damage to it.
The entire system will actually provide cameras for monitoring how many people are in the chapel, and properly cull all the dirt and debris that is produced by the upwards of 2,000 people moving through the chapel regularly. This will better condition the air, and make the frescoes of the chapel less likely to be damaged in the future.
Overall, the project ended up consuming millions in dollars, and it is slated to be finished sometime next year. And it all started because of the air quality in the Sistine Chapel.