I found this pretty interesting.

The ancient tombs kept under lock and key - BBC ReelBEST OF 2019: A sense of mystery surrounds the keyhole-shaped kofun tombs in Japan. Although the iconic Mozu Tombs in Sakai city, Osaka have recently been awarded UNESCO World Heritage status, surprisingly little is actually known about these intriguing monuments, kept under lock and key by the Japanese government.www.bbc.com

Interesting. I was wondering if people would say ancient aliens did it or something like the pyramids and sure enough they do. Thanks for sharing.

Fascinating! As one who is learning Japanese, this was an interesting cultural lesson. Thanks for sharing!! どうも ありがと!!