The unfinished Port de Rat Tunnel
Located in the Pyrenees mountain range, the Port de Rat tunnel is an unfinished high mountain tunnel, which had to connect Andorra and France.
Now it is a cave, but it had to be a connecting tunnel between Andorra (at 2.370m above the sea level) and France (at 2.157m). An important economic effort that the French government was forced to back down due to lack of funds. Only the Andorran slope of the Pyrenees was drilled and now it has become a tourist attraction in the ski resort of Vallnord. It was a combined project of both countries, born in the second half of the twentieth century that would have been a revolution in the economy, by allowing easy access to the thousands of French travelers who visit this small country every year. Only the excavation of the tunnel on the slope of Andorra was started. The French government never got to gather the necessary funds to carry it out.
Pic&more info: http://www.ordino.ad/turisme/natura/Senderisme/camins-de-llarg-recorregut/el-port-del-rat