In climate history and geology alike, an interglacial period is a phase with higher mean temperatures, located between two periods with lower mean temperatures – ice ages.
Throughout Earth’s history, there have been massive climate changes (ice age cycles). The warm phases are referred to as interglacials; the cold ones, as ice ages. We are currently living in an interglacial, the Holocene. The last such phase was the Eemian interglacial, roughly 125,000 years ago.