Nyiragongo is among the most active volcanoes on Earth. Since the first observations by European explorers in the late XIXth Century, its eruptive activity mostly concentrated into its main crater, with the presence of a persistent lava lake. The characteristics of this lava lake have evolved through time. The lava lake and the uppermost magmatic system were drained during devastating flank eruptions in 1977 and 2002. Despite a large scientific interest and even larger societal concern, Nyiragongo remained little studied until recently. In this presentation, we will review the key scientific knowledge about this volcano, highlight inaccurate or divergent information and demonstrate the limits of possible interpretation. The lava lake drainage in 1977 and 2002 was the consequence and not the cause of the flank eruptions. Field observations as well as seismic, petrological and geodetic results indicate that these flank eruptions have an intimate link with deep magma intrusions and rift tectonics. Recent results based on ground-, air- and space-based techniques provide new insights into the evolution of the Nyiragongo lava lake since 2002, and more specifically on the lava lake level variations observed during the past 5 years.