At roughly the size of a house, the average hot-air balloon is mighty impressive. Now imagine more than 700 of them all around you, slowly inflating and lifting off into the sky like the preamble to the world’s biggest birthday party. This is the Albuquerque International Balloon Fiesta, the world’s largest hot-air balloon rally. It’s impossible not to get swept away by the colour and excitement, even if it is near dawn and freezing cold.