Introduction to Alcantara Bridge: Puente Alcantara Bridge (Puente Alcantara), also known as San Martin Bridge, spans the Tagus River. It was once the only channel connecting the ancient city and Waikai. At that time, a Spanish princess walked across this bridge and crossed the Pyrenees Mountains to marry in France to join the political alliance in Spain. In the end, she was quietly strangled to death because she did not please her husband; and a few years later, a French princess also passed through this bridge. He walked into Spain through a bridge and finally conquered the country with Catholicism.