DIY swinging bookcase doors are everywhere but I built the world's first hidden door bookcase that lifts up like a gullwing door to reveal a secret room in my house. Most secret doors swing like a normal door but because I have carpet that wouldn't work. It would have revealed the secret room behind it so I had to use gas struts to lift the bookcase up. No thief or burglar can find it so I can keep my hidden treasure safe.