The PS3 can play PSOne (PSX) games from disc? Mind Blown!!!!

While browsing NEOGAF today, I found a thread from a user who. like myself, had no idea the PS3 could play PS1 games.

I never knew this was a thing. I thought that Sony had scrapped their backwards compatible after the first edition models but that was only for PS2 emulation, the PS1 was kept intact throughout.

Im baffled right now, was anyone else unaware of this?