Syakado Kiritoshi (釈迦堂切通し) is one of the historical and great nature monument in Kamakura. It was build around 1200 by cutting and digging small rock valley for transportation. The shape of the tunnel is still preserved from Kamakura period. It was name by when Yasutoki Hojo (北条泰時) built temple for the memorial service for his father.
Tourist Info.
You can access this tunnel, but technically you cannot go through. Be careful, after rain there are many risk to have rock falling. It will be all self-responsibility whatever kinds of accident you have.
Access
0. at Kamakura Station.
1. use Keikyu Bus to Sugimotohonzan (20 min.)
2. walk south (15 min.)
20 min
Let's learn MJER Iaijutsu. 
映画好き集まれ！ 
One of the greatest nature monument in Kamakura. It was used to be cutting transportation during the Kamakura period.
You could see the great rock bridge made by men about 700 years ago, and the shape of the tunnel is still almost same as used to be.
Even in the summer, the tunnel and the spots is very cool and quiet.