Dark Cave has no ambient light in-game — you need Flash (or, from Crystal onward, the Mahogany Gym badge toggle) to see anything here. This map renders the cave fully lit for legibility; the in-game view is otherwise pitch black beyond a small radius around the player.
Mt. Silver Cave 1F has no ambient light in-game — you need Flash to see anything here. This map renders the floor fully lit for legibility; the in-game view is otherwise pitch black beyond a small radius around the player.
This map follows Pokémon Crystal, where Lugia waits in its own chamber behind the Silver Wing. Gold and Silver have no such chamber — there, Lugia is on the lowest cave floor reachable from the Northeast entrance, which this map does not show separately.