Classical Tauroctony reliefs from across Europe, depicting Mithras slaying a bull.

Mithraism, a Roman mystery cult inspired by the Iranian deity Mithras, was once an incredibly popular and secretive faith in the Roman Empire. For a time, it was considered the main rival to Christianity as the most popular faith besides the Roman state cult in the empire.

Paintings of domestic animals by contemporary Dutch painter Bas Nijenhuis.

Paintings by German artist Peter Witt. All of these works are currently for sale, for those interested!

Woodblock prints by Japanese printmaker and lacquer artist Shibata Zeshin.

Photographs from the iSpy series of books, taken by photographer Walter Wick.

What was your favorite iSpy? Mine was Treasure Hunt, a page of which can be seen here.