Booked this on same day, easy to use tool. Basilica Cistern is an engineering wonder - a must see!

At first I thought it’s a church. I am wrong, it’s a water system, but interesting to visit. Skip the line is powerful, no need to queue ☺️ And dont forget to download the audio guide.

online tickets do get a shorter queue but this applies to online tickets bought on the official passo portal too. the problem was I bought the audio guide too from Pelago but was not given a separate audio guide link at time of booking. this resulted in me being stuck at the entrance frantically trying to contact Pelago as the staff there refused to give me the audio guide since I had no QR code to show. Pelago had to contact their local partner so it took them another 15 mins to send me the audio guide, by which time I had given up waiting and entered the Basilica Cistern which was underground and had no internet reception. By the time I received the audio guide I had already finished touring the place, but luckily the provider agreed to a refund of the audio guide portion after I asked Pelago.