In addition to the Rotonda, this is one of the two most characteristic monuments in town. The Galerius arch is situated close to the eastern city wall, a short distance from the Kassandreotiki gate. The 4th-century AD Roman emperor Galerius commissioned both structures to show off his power. A road used to run through the arch, past the Rotunda and on to the palace to the southwest. The arch is composed of a masonry core faced with marble sculptural panels celebrating a victory over the seventh emperor in the Sassanid Persian Empire. About two-thirds of the arch is preserved. Colloquially, the monument in known as Kamara, that's Greek for 'arch'.

This is a beautiful way to learn about the natural history of Hawaii. The guides will walk you through the gardens, the plants, and all the movies and shows that have been filmed there.

The Basilica of the National Shrine of the Immaculate Conception is the largest Roman Catholic church in the U.S., with a striking interior of mosaics, chapels, and domes. Free guided tours are available and give a good sense of its history and architecture.