I have started small project of exploring the BDO map and searching for cool places and hidden areas.
So far I have a video list of Secret Caverns in the game.
Most of the times you need to have a lantern with you while running in those caves.
(Hidden BDO) Secret Caves in BDO so far: youtube.com/playlist?list=PLQNXzixfUijoirV1O1wKfLF6dxZKdaCpG
My youtube channel: youtube.com/channel/UCRItyUTQLTvjT24DUmX6jWw
My stream: twitch.tv/pohjantikka