Fukahori Shrine is a sacred site where the spiritually minded come together to pray. Take a few reflective moments yourself, or simply observe others in worship.
You'll be spoiled for sightseeing choice when spending time in Nagasaki. Fukahori Shrine is a good place to start here, but there are many other worthwhile places to appreciate. Glover Garden, Oura Church, and Megane Bridge are close to the sacred place and and will cap off your day nicely.