[Read] The Dark Net: Inside the Digital Underworld Complete

Inside Global Underworld - Dark Side Of Trade (全球地下黑市)

Digital book The Dark Calling (The Arcana Chronicles Book 6) Complete

The entrance to the underworld inside a cave

In 2011 a Belgian photographer was allowed entry into one of Japan’s Yakuza families. Over two years, he captured the lives of those living in the underworld. - Japan's Yakuza: Inside the syndicate (2015)