There are 23 Helix Glitches in the Thames district of Assassin’s Creed: Syndicate. These collectibles reward you with a small amount of XP and when you find enough of them you might also get some Helix credits. We decided to create this screenshot guide including a detailed map with all Helix glitch locations marked, because purchasing an in-game map requires you to spend precious helix credits (you can get them via spending real money or by collecting helix glitches, which is kind of counterproductive). We went from the south side of the Thames upwards. We recommend you go through some of the main story, until you get the rope launcher form Alexander Graham Bell (I believe you get this during Sequence 3).