ON FEBRUARY 12, 2005, a yellow balloon was launched into the sky over Beirut. It was a tethered helium model known as the Aerophile 30, large enough to carry a small group of passengers nearly a thousand feet aloft. An earlier version, installed in Paris’s Parc André Citroën, had been a popular and commercial success, offering adventurous riders a unique vantage onto the city’s landmarks. There, the urban park was a natural location for such a project, allowing the balloon to rise dramatically over a sweeping green expanse. But the nature of open space is fundamentally different in the constantly