We had no plans for Valencia as the information online about visiting this port was limited. We were lucky enough to speak with a Spanish couple on the ship in the morning.
They had been to Valencia in July and thought that the Museum of Arts and Science was worth checking out. We could see this architecturally stunning building from the ship, but it was even better up close. It has a space age look and is surrounded by water features. It is connected to a wonderfully long park similar to Central Park or Golden Gate Park with ample pathways for walking or biking.