Scientists have identified the “mystery volcano” that erupted in 1831 and cooled Earth’s climate. They have linked it to an island volcano in the northwest Pacific Ocean.

In 1831, somewhere on Earth's surface, a portal to the underworld appeared. A massive volcano opened wide its jaws and belched forth so much ash and smoke that the skies dimmed, cooling the Northern Hemisphere.

The researchers conclude that the 1831 Zavaritskii eruption had a magnitude of 5 to 6, similar in power to the 1991 eruption of Mt. Pinatubo in the Philippines, one of the largest volcanic eruptions of the 20th century.