Grade separated or multi-level cycle facilities where bike paths overpass or underpass roads and junctions are quite normal in the Netherlands. Most of these were built relatively recently. In Utrecht there is a multi-level cycle roundabout that is a lot older. It turns building started as early as 1939! Building it was finished in 1943. It is still used almost 70 years later!
A 70 year old multi-level cycle roundabout in Utrecht