Erta Ale volcano's lava lake back in Nov 2009. The red glow of the lava illuminates the crater walls under the blue sky of dusk. A small group of observers is on the left crater rim. During the past 7 years, the lava lake has gradually risen. As of now (Dec 2016), the lava lake has completely filled the pit crater and constructed a new shield by ongoing overflows. (Photo: Tom Pfeiffer)