I was in Frankfurt last week delivering a training course. The return plane made its descent over central London after night had fallen. Clear, cold air and no clouds to interrupt a magnificent view of glittering lights as we slowly tracked the Thames from 5000 feet up. Canary Wharf, Regent's Park, Baker Street were all laid out like tiny versions of their normal selves. Everything seemed 2-D, buildings that normally tower and arch above my craning neck and slack-jawed face were puny and inconsequential on the bigger patchwork blanket of London at night.

Bizarrely everything was sparkling, occasional blasts of light appeared at junctions below, green or red or yellow puffs of flame balling into the night and dying. It looked like a Bladerunner clone - fireballs against a neon backdrop - and I could not work out what was going on, the only theory I had was that it was some sort of celebration for the fall of Kabul, but that seemed unlikely. The pilot later informed us that it was a celebration of Diwali (the Hindu festival of light).

Later, from the Heathrow Express, the fireworks were all around and not below. More impressive in their immediacy, less imposing in their scale.