Marni Hill is the high point of Petit St. Vincent at 275 feet — not high in any objective sense, but high enough to give a complete view of the southern Grenadines in good weather. A graded path winds up through tropical scrub and ends at a small clearing with stone benches. Walk early, before the heat, with water; the round trip takes about an hour.
The view takes in the whole island, Petite Martinique just south, the Tobago Cays archipelago to the north, and on clear days the green hills of Carriacou and Grenada away to the south. Sunset is the obvious time, but the wind picks up in late afternoon and the descent in the dark is genuinely dark — bring a head torch.