DOOR DETAILS: The door looks like a normal glass door with a bar to pull it open. There's a curving stairwell immediately visible on the other side.
LOCATION TYPE: It's a workshop, but we have a bunch of workshops now, so I'm calling it a garage. But it's a workshop.
LOCATION DETAILS: Following the curved staircase brings you down to a glass wall and a locked door. Until now, anyone can walk in, but beyond that point you need a passkey. Occasionally this wall may be opaque, so some knocking may be required to gain the occupant's attention. Within the room all manner of engineering projects may or may not be underway - there's a car missing some pieces there, half an Iron Man hanging around, and a bevy of holograms and table top messes. Also, you might be lucky enough to meet DUM-E if you come in. I'm kidding, if you come in you're definitely meeting DUM-E, whether you wanted to or not.
FURTHER NOTES: Canon location from Iron Man 3 (MCU).