Beneath the decorative domed ceiling in the centre of the building, there was a large Foucault's pendulum swinging back and forth.
Below the original building were exhibitions in more recently constructed levels - including an impressive area devoted to the planets:
There was plenty to see outside, the Observatory's terraces providing a great view over the city below:
Back inside though, the highlight of the visit for me was the demonstration of a Tesla Coil, a device which was developed to transmit electricity through the air.
I even caught one of the demonstrations on video. Here it is - click and stand back: