I've figured out where people lived based on sunset times. Sunset is a prayer time in Islam, so sunset times in most cities in the world is accurately calculat

I've figured out where people lived based on sunset times. Sunset is a prayer time in Islam, so sunset times in most cities in the world is accurately calculated. Sunrise too. The window for a sunrise and sunset is about 5 min, which should give you decent accuracy. You still need latitude though.