To your right, you can see the famous cave of Aira Sanryo Mausoleum.

It belongs to Kamu-yamato Iware-biko, or to say, Emperor Jimmu, the first emperor of the Imperial family,

There are also his parents:

The two deities Ugayafukiaezu-no-Mikoto and Tamayori-hime-no-Mikoto. They are also entombed here. Jinmu's father and mother, respectively.

It is the only cave among the imperial mausoleums managed by the Imperial Household Agency...

That was a good question!