Across the street from Piazza del Plebiscito, the Acton elevator takes you down to the port:
The pedestrian walkway along Via Chiaia connects Piazza Trieste e Trento (by the Teatro San Carlo) to the upscale stores near the Bay of Naples. Smack in the middle of this walkway is an arch:
Inside, an old staircase as well as an elevator takes you up to a less visited part of the city. Here, you can see the Palazzo Serra di Cassano (owned by a Prince whose son Gennaro was executed during the 1799 revolution), the Museo Artistico Industriale, and Pizzofalcone (the birthplace of the siren Parthenope). The elevator itself is manned by friendly operators, so there is no need to press any buttons yourself.
Finally, in the seedy Sanita section, a bridge going toward Capodimonte has an elevator that goes down to the Church of Santa Maria della Sanita. This spooky Church has translucent angels at the altar and the San Guadioso Catacombs.
But watch out! The elevators also have hours of operation. When the green light is on, the elevator is open. When the red light flashes, the elevator is closed.