One team of archaeologists put several ancient lighting systems to the test to get a better picture of how our ancestors illuminated the darkness.
In a study published in the journal PLOS One, the team described three tools that Paleolithic-era humans likely used: torches, fireplaces, and grease lamps.
Trace remains of all three tools have been found in caves in Southwest Europe.
Their results: Torches burned the brightest, and kept their flame for an average of 41 minutes.
Fireplaces performed the worst. The team only built one, and it burned smokily until extinguishing after 30 minutes.
However, the team reports that the air currents in their test cave may have not been the most ideal for this type of lighting.