The Kalighat Kali Temple is one of the 51 Shakti Peethas — sites of supreme importance in the worship of the goddess. It draws tens of thousands of devotees every day, and the atmosphere inside is intense: priests chanting, bells ringing, the smell of marigolds and incense, and a constant press of worshippers. Non-Hindus are permitted inside, though the inner sanctum can get extremely crowded.
The temple as it stands dates from the early 19th century, though a shrine has stood here far longer. Before your visit, hire one of the official guides at the entrance — they help navigate the protocols and explain what you're seeing. The surrounding lanes are worth exploring for the shops selling clay images and ritual supplies. The nearby Nimtala burning ghat adds to the sense of a place where life, death, and devotion are all conducted in the open.