How Golda Meir, Indira Gandhi, and Margaret Thatcher Wrought a New Standard of Leadership. It is surely time to recognize what an immense improvement has been wrought in world standards of governance by the rise of female national leaders.
Shield volcanoes, the third type of volcano, are built almost entirely of fluid lava flows. Flow after flow pours out in all directions from a central summit vent, or group of vents, building a broad, gently sloping cone of flat, domical shape, with a profile much like that of a warrior's shield.
Lava tubes are a type of lava cave formed when a low-viscosity lava flow develops a continuous and hard crust, which thickens and forms a roof above the still-flowing lava stream. Tubes form in one of two ways: by the crusting over of lava channels, and from pÄhoehoe flows where the lava is moving under the surface.