Varanasi, one of the holiest places in all of India. It is also one of the busiest and crowded towns I have ever seen. Traffic is totally nuts.
The Ganges is considered sacred, followers come from far and wide to be cremated along the Ghats (steps) of the river. The water is considered holy and every morning people come to bath. It is very polluted but they believe that god with reverse any negative effects and purify the water.