Tremble at These Surreal, Sky-High Urban Roller Coasters

Terrified of heights? Then you might want to turn away from these photos, which show roller coasters so tall that to get to them you'd need the Space Shuttle. One can only imagine the nauseating progression of screams as the brutal g-forces slammed in: wheeeeeeeaaaaaaaaOOOHHHGOD!!

These heady manipulations are the work of Robert Jahns, a 26-year-old art director from Hamburg, Germany. Jahns started in the digital arts 15 years ago with Photoshop, but technology has advanced so rapidly that he now makes his stunning images with just an iPhone 5s and a few apps (ArtStudio and Filterstorm, for instance). The visceral impact of his work is obvious in the hundreds of thousands of people who follow his nois7 Instagram; typical fan comments include "best feed ever!," "I'm still trying to pick my jaw up off the floor," and "Thanks for making me dizzy while I'm sitting down."