Before going on my 3rd trip to Berlin, I decided to read about clubs and I've seen places calling Tresor "A tourist trap", which I have to disagree.
1st of all, there is A LOT of cry babies posting reviews, that know NOTHING about Berlin amazing door policies. Yes , I said amazing, because you are not allowed to use your phone like an idiot or take pictures for your favorite social media. If you are a tourist, go by the rules, this is their home not yours, so if you want to get in make sure you respect the rules (Both oficial and unwritten ones. Ask the locals). Oh and I don't speak german, yet got inside with no problem at all.
In this trip I was looking for a genuine, underground techno club, with a dirty feeling mixed with freedom. I found it in Tresor, right in my first night.
When I got inside, I went upstairs as my friends wanted to, and I felt disappointed because the music was too light. However, I decided to go downstairs, and that's where the REAL PARTY begun. The underground room is A MUST! Dark, lots of smoke, hard loud music, orgasmic sound system, amazing people, and the list goes on and on and on. The access to that room is the typical thing I was looking for, a dark tunnel with markings on the wall, sparkling lights and smoke. I really enjoyed the whole experience. You have several bars, many rooms where you can sit and chill, or the upstairs room if hard mode is not your thing.
11/10 would go again. Next time in Berlin I will repeat this. Please don't change :D