Board a boat in the bustling harbor of Porto Antico for a day of whale watching, or a quick trip up the Ligurian coast to the tiny enclave of San Fruttoso, an abandoned Monastery standing guard over the sunken statue of Christ of the Abyss. Bring your scuba gear for spectacular views of this hidden abbey, completely cut off from the world except for a steep mountain side hike or a ferry from the dock of a neighboring village.
Although the aquarium itself leaves something to be desired, if you do choose to go (if you have children, it can be a great morning outing) make sure you take a few minutes on the top floor to soak in the harbor panorama.
In the summer, the small port is often filled with small luxury yachts, and the view of the biodome from above is neat. You can also see the Lantern of Genoa, and sunsets over the water are quite beautiful, especially in the warm evenings of late spring.