Citymapper

Yes, it is great. I dont know how many cities around the world it covers, but we used it recently in New York City, and it worked great for managing the subway.

CityMapper is not ubiquitous throughout the continent of Europe so old fashioned map reading is still very important!

I have used it in Boston and Paris, in addition to London.

Thanks for the info, I just downloaded it and am playing around with London, our next trip.

My favorite part of it was when we were enjoying ourselves walking around on the first level of the Eiffel Tower and this obvious tourist couple were sitting there pouring over a map of the Paris Metro, in obvious confusion. I smirked, went on my way, and still never looked at a Metro or Tube map all the time I was there. I couldn't have helped them look at that map even if I wanted to.

Yes, I use it daily even though I have lived here for 13 years. Use it every time in London, too. Have also used it in Rome, Stockholm, Washington, and I can't think where else. It is a game changer. I don't know who their engineers are — and how they integrate all the transit and traffic data so seamlessly — nor their interface designers, but they have really created something invaluable for city travel. (Love their little icons for each city and their jokes too.)

@contintental. Absolutely agree with you that reading paper maps being a unappreciated skill. Hold on to the ones you've got before they stop publishing them.

Is it possible to use the app offline?

Yes and No... when in London I made sure to load in the destination before going down to the Tube where there is no Data or Wifi. It won't update times but you can scroll through the various pieces of your trip down below so it will tell you where you have decided to go. You can't update it unless you find a signal somewhere. Basically as long as you had loaded in a trip before you lose service you're fine. In Paris it was no problem as I had data down in the Metro.

Is this kinda like have a mapquest route on your cell?

Yes, in a way. But it gives you so many varied options I found it incredibly helpful. I wasn't planning on using it until so many people noted how useful it was and since I was getting my own SIM for my cell and I had lots of data I decided to use it and it was amazing. For someone there for just a few days it was so easy to just follow the directions. We detoured across town a few times simply because it was so easy to get somewhere. "22 minutes to Piccadilly Circus" it would tell me, from exactly where I was standing. No brainer, it was great.

If you're hesitant give it a try. Get the app, plan a journey in it with a start and end location (your hotel to the London Eye for example) and just look at all the different options it would give you. I also used it a few times to find how long it would take to get somewhere the following morning so I would have a ball park of when we needed to leave.

The only caveat I like to give about Citymapper, is that it can be a power hog. I gave it a test drive in my own city, and while it worked really well, I found it seemed to drain my battery very quickly.

So if you can, test it out first, and see how it works for you.