Cathedral of Saint Andrew is not just a place of worship, but a worthwhile attraction too. Make a pilgrimage and enjoy a moment of contemplation.
You'll be spoiled for sightseeing choice when in Patras. Cathedral of Saint Andrew is an ideal place to begin here, but there are many other interesting places to consider. University of Patras, Georgiou I Square, and Rio-Antirio Bridge are near the house of prayer and will fill in your day nicely.