This week's Good Facility (courtesy of HackneyCyclist) is a bi-directional cycleway passing directly under a taxiway at Amsterdam's Schipol airport. This cycleway runs alongside a road and a waterway, under the runway, and is a direct connection between Amsterdam and the town of Hoofddorp. There is also a parallel service road (with separate cycling provision) on the other side of the waterway, all passing under the runway.
This facility is also a useful demonstration of how cycling infrastructure (which only needs to accommodate humans) doesn't need as much height clearance as a road, which has to accommodate large lorries. So the cycleway here only dips down a small amount, meaning it requires less effort to negotiate.