Today was the first day of Tour of Watopia Stage 4, the second to last stage of the series. This stage is also the first time we have seen Zwift use a gravel surface rather than the traditional dirt surface in the jungle. The main differences are the color, speed, and dustyness.
The difference in speed is that this is somewhere where gravel bikes will likely be faster than mountain bikes. On almost all courses, a mountain will beat a gravel bike. This also allows for a bunch more things like a gravel Alpe, Cobbled jungle, or a super smooth glass feel in NYC! Some riders have been complaining that you can only use the Zwift default gravel bike on this stage, but this could be because the Zwift gravel may be specialized for this stage/surface, meaning it could be a lot faster than a mountain bike or other gravel bike on this course.