What is the longest line of opening theory you know?

I personally don't like studying certain lines in opening theory, but I have this one memorized: 

(For app users who can't see the board: 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 d5 5. exd5 Na5 6. Bb5+ c6 7. dxc6 bxc6 8. Bd3)

What is the longest line of opening theory you know? Share it! 

E4 E5 Nf3 Nc6 Nc3 Nf6 Be3 Be6 O-O O-O

Idk if the end is theory but it is what we would always play in my old OTB club

I think I miscalculated it

Well I'm the same with my theory line, I think it counts ig

You meant Be2 Be7?

Oh yeah it is Be2 Be7, wrong bishop

I think a more common choice in that opening would be Bc4 Bc5, but whatever

e4 e5 Ke2 Nc3 Nf6 Ke3 Bf4 Ng8

Ke2 ?

I dont know openings

It should be a line in the Ruy Lopez, I think it’s over 15 moves and I of course dont remember all the moves

I came up with an improvement on move 28 over Sznapik vs Ljangov, Sandomeirtz 1976.

This Catalan Mainline is the longest one I know so far:

Wow that's crazy