Red Door...

Alice took her new toy camera Digital Harinezumi to Lisbon and found this red door. The camera is quite amazing because the colors came out very vividly. The fact that it is a digital camera/video camera also allows impatient Alice to see/upload her pictures immediately.

Alice found this red door in Lisbon, near the Castle of São Jorge. There are not many red doors in Lisbon and Alice just thought this door looks really impressive. Inside the door is a courtyard, then another red door. On the front door, the word 'palace' indicates that this may be a special building, but Alice couldn't find any information about it. It looks like one of those secret society from The Avengers TV shows.

What secret soceity operates behind red doors?