Hakusan Jinja (白山神社) is a Shinto shrine established in 948. It is not a large shrine and there's not so much to see here, but in mid-June, Hydrangea Festival is held here.
Hakusan shrines are spiritual branches of Shirayamahime Jinja in Ishikawa Prefecture, which worships Mt. Hakusan.
It's a 1-min walk from Toei Mita Line Hakusan Station, or a 5-min walk from Tokyo Metro Namboku Line Honkomagome Station.
Chozu-ya is where you purify your hands before offering prayers.
Haiden is where you offer prayers.
Honden, located behind Haiden, is the very building divinities are enshrined.
The Ajisai Matsuri, or the Hydrangea Festival, is held in mid-June when hydrangeas blossom. On weekends, there will be some events like small open-air concerts. For details about this event, see the article on the Ajisai Matsuri at Hakusan Shrine.