An undated handout photograph shows divers inspecting a basalt rock formation near Penghu. A biodiversity researcher has found a huge basalt rock formation in the Taiwan Strait, resembling a city wall and rivaling similar monoliths on land. The 200 metre-long, 10 metre-high undersea wall, which looks like thousands of pillars packed together, is near the Pescadores archipelago, researcher Jeng Ming-hsiou said on Monday. [Agencies]