Pandals and idol are sometimes inspired by a particular theme, but this decision always belongs to Puja committers. Very common and popular thing is 'pandal hopping', where families and friends visit other pandals. We did that in Salt Lake City, Kolkata. We visited over 15 local pandals, most of them were very traditional. Actually our journey through the neighborhood I can call 'rickshaw pandal hopping' and I think that was very good idea to choose a rickshaw over a car to see other pandals as no parking needed and the distance between one and another pandal was short as well. Here are some of pandals we did visit. Amazing!
The one below was a 'bird theme'. The pandal itself looked like a nest from the outside with two huge eggs on the roof. I don't have a picture of that unfortunately.
The Salt Lake FD Block came up with a huge pandal and beautiful statue of Durga:
It's very hard to believe that all statues are going to be immersed in the holy water of river Ganges on the last day of festival and all pandals are going to be destroyed.