Sensoji temple, located in Asakusa district, is one of the most famous temples in Tokyo. Then, it is not just a place for tourists but many local Japanese visit too.
Asakusa district used to be the biggest entertainment district in Tokyo till the half of 20th century.
The first subway in Asia, the Ginza line terminates at Asakusa station(it is very interesting that the Ginza line does not go to Shinjuku station, which is the busiest station on Earth).
Landmark of Sensoji is the Kaminarimon(Thunder gate) with a huge Chochin(Japanese paper lantern) written Kaminarimon.
After passing the the gate, you will walk along a street with many small shops on both sides of the street, where you can buy souvenirs. Souvenirs include traditional Japanese crafts and for foreign tourists. Also, you can taste the foods which are sold by the vendors.
One interesting thing in Japan is that you will meet teenage Japanese at these temples or shrines. These teenagers are rare to be seen at castles or museums. However do not expect them to be deeply engaged in religions.
I assume that their main purposes are to try the foods sold by the vendors or taking photos for their Instagram accounts. Actually I think their purposes are to take a photo of the food for their Instagrams!