Visible in the dry hills to the north of Nice is the white dome of the city’s observatory, founded in 1881 on the summit of Mont Gros. Guided visits (in French) run at 2.45pm on Wednesday and Saturday, plus Friday during school holidays. Bus 84 leaves a few times daily from Gare Riquier, several blocks north of the port; get off at the Observatory stop and walk 20 minutes to the observatory.
It’s about 6km drive from Nice’s eastern outskirts, otherwise there are instructions for how to get here on foot on the Observatory website. English-language tours for large groups can be organised via email.