I live in a downtown apartment and have to put up with traffic, drunken shouting, sirens, garbage trucks, car alarms...I still manage to sleep but after trying this app Im hooked on it for the sleep function alone. I can set the length of time it plays and, whats really cool, the length of time that the soundscape fades to silence and off. I immediately bought two of the packages offered, so I now have over 30 soundscapes to choose from. These folks have done a really good job of seamlessly editing the sound recordings so that the infinite looping is "invisible" at the point where it loops. (I suspect they used multiple overlaid tracks to do this.) This is not artificially created sound but real, live, recorded in nature (except for a few weird ones like the Apollo spacescape, which I dont much like). I recommend this to anyone wanting to just enjoy some natural sounds--in the office, the home, in bed, on the road. And--bonus--they get back to you really quickly (like, overnight) if you have a question. Well worth the additional price of the in-app purchases, but you can try the ones included in the original app download first.
UPDATE: latest track is called ECHOLOCATION and is very unique in that they have slowed down the otherwise ultrasonic (inaudible to us) sounds of bats, and inserted them into a regular speed recording of the environment they are in. Its really cool. I cant speak highly enough of NatureSpace, and to give you an idea of how useful it is, my mother is currently dying at home, under nursing and family care, and i have played some calming Naturespace tracks and I do believe she sleeps better. I know I get to sleep better with a half-hour of waves or wind (dont need the rain tracks in the Pacific Northwest!).