This gravel mountain is a part of Ginkaku-ji garden and it's called Kogetsudai [translates as "moon-viewing platform", maybe because the shape resembles the moon's reflection on water]. Some people say it represents Fuji mountain, but I wouldn't draw conclusions too fast: Zen buddhist symbolism is usually more complex than that.
Behold! This is Nyannyan-ji, or "Meow-meow Temple", the only temple in Japan (maybe in the world even), where the priests are all cats. I couldn't meet the current sandaime (third generation) head priestess Koyuki because she was asleep, but her well-dressed 11-y.o. assistant Konatsu was also very impressive. This bizzarre place was created by a shrine/temple painter Toru Kaya who was inspired by his beloved pet. Although technically it is not a functioning temple (no religious ceremonies are held here), the altars look quite serious - you can notice offerings of canned cat food, flowers, statues and other buddhist attributes arranged pretty professionally.
Tripadvisor has very mixed reviews for Nyannyan-ji: people either love it or get super frustrated because they travelled a long way to find a "fake" temple that looks more like a cat cafe and a souvenir shop combined. As for me, I am definitely on the first side: I got another chance to admire the extremities of Japanese cultural open-mindedness.