Mosaic City, located along China's coast, is quite large city sometimes called the Crossroads Between Nations due to its diverse population. While it was once a large tourist spot, the city was placed under a blockade as the military appeared claiming there was a radiation leak. The true hazard, however, is much more sinister.
While no longer in operation, this subway tunnel leads to outside the circle. Though, it is heavily populated with shadows and is quite dangerous for anyone unprepared. It has been deemed off limits by the police, but it seems to be the best way outside the circle.