Approximately 2 million years ago in the Pliocene era, the area of what is nowadays Grenada emerged from a shallow sea as a submarine volcano. In recent times, volcanic activity has been non-existent, except for some of its hot spring and underwater volcano Kick 'em Jenny. Most of Grenada's terrain is made up from volcanic activity that would have taken place 1-2 million years ago. There would have been many unknown volcanoes responsible for the formation of Grenada including Grenada's capital St. George's with its horseshoe-shaped harbour, the carenage. Two extinct volcanoes which are now crater lakes, Grand Etang Lake and Lake Antoine, would have also contributed towards the formation of Grenada.