It's a temple with a bunch of street food and souvenir shops around. This area has an old-fashioned, traditional Japanese atmosphere. Usually super crowded with lots of tourists from the world, but definitely worth going. But I definitely recommend you to leave huge pieces of baggage! It's that crowded. Otherwise, they'll annoy you.
1 Chome-5 Asakusa, Taitō, Tokyo 111-0032, Japan