These days, I like to get most of my daily five miles of walking in the evening, when the air is cooler and the city seems quieter. Evening walks are more meditative than running around doing errands during the day. I notice more: the sky, the trees, people passing by.
There have been some colorful sunsets recently, although I'm usually not the right place to get the full effect. But here's an iPhone shot of the Public Garden Lagoon the other night. The sky was fiery red beyond the treetops. And one streetlamp flared greenish across the water, like a tiny UFO.