Unlike the Alps that have century old routes across, the Pyrenees continue to be a major barrier to land travel. Virtually all routes of note that cross do so outside the central (highest) part.
A high speed rail line links Perpignan and Figueres and connects to the French TGV and Spanish AVE networks. Another rail line at the western edge contains a break of gauge and is thus used more rarely these days.
The mountain range crosses three countries:
The entire country is contained within this mountain range
Few major cities are to be found directly inside the mountain range
This is a high mountain range, with peaks up to 3,404 m (11,168 ft) high so you should be prepared for what that entails, including sudden changes in weather, severe weather, avalanches and other dangers of the mountains. The Pyrenees are also one of a few regions of Europe still containing bears, which usually don't bother humans, but can attack and even kill when drawn in by food or if humans get between a mother and her cub.