Sundarbans
The Sajnekhali Wildlife Sanctuary at the entrance to the Sundarbans core zone is home to a remarkable variety of birds — open-billed storks nesting in the treetops, kingfishers darting along every creek, white-bellied sea eagles soaring overhead, and waders working the mudflats at low tide. The sanctuary also has a small crocodile and turtle breeding centre and an interesting interpretive museum about Sundarbans ecology.
This is typically the first stop on any Sundarbans tour and sets the context beautifully for everything else you will see. Do not rush through it.