If you look at a map, Corsica appears to be located at a considerable distance from Europe. Yet, at sunset and with favorable meteorological conditions Corsica can be seen from Nice and the surrounding areas.
Of course, one can only see the mountain tops due to the rounded shape of the earth and low-lying fog which hides the rest of the vista. To see the Corsican coastline one needs to climb to a higher elevation in the Nice region to compensate for the curvature of the Earth.
View from the lighthouse at Garoupe (256 feet in altitude) at Antibes.