A Portrait of Nikola Tesla in an Orthodox Church in Serbia
Tesla has not been canonised, but as a great scientist he is regarded by the people as a saint of a cultural order. Hence his portraits, and even icons bearing his likeness, may be found in churches, though this is the private initiative of parishes, priests or parishioners.
Incidentally, Tesla was the son of an Orthodox priest. And in Serbia the question of honouring him within the Church, or at the very least of commemorating him respectfully with a tribute in the form of a memorial corner in churches, comes up again and again.
Such is the phenomenon, verging on a form of religious cult.