Rainbow Valley, on the southern side of Hormuz, is where the island's extraordinary geology puts on its most dramatic display. The soil and rock cycle through bands of deep red, rust, ochre, violet, yellow, and white — the product of different mineral concentrations including iron oxide, sulfur, and magnesium. On sunny afternoons the colours are almost impossibly vivid.
The valley is best reached on foot or by motorbike from Hormuz town, a journey of about 4 km across the island. The walk through the interior is itself worthwhile — the landscape has a lunar, almost hostile quality, with sparse vegetation and rock formations eroded by the wind into organic shapes. Arrive before 3pm if you want the best light on the colours; the west-facing slopes glow most intensely in late afternoon.