These remote Arctic islands are the remnants of a vast, now-submerged prehistoric plain.

Countries & Cities · Published 30 September 2026 Swipe more like this →

In short: Lying north of the New Siberian Islands, the uninhabited De Long archipelago is a geological time capsule. Once high ground on the massive Great Arctic Plain, these peaks were isolated when rising seas swallowed 1.6 million square kilometres of land during the early-to-middle Holocene, leaving only these rocky fragments behind.

The De Long Islands—comprising Bennett, Jeannette, Henrietta, Vilkitsky, and Zhokhov—represent a tiny fraction of a landscape that once connected Siberia and Alaska. During the Last Glacial Maximum, when global sea levels were 100 to 120 metres lower than today, this region was part of the expansive, unglaciated Great Arctic Plain. Protected by the rain shadow of the Northern European ice sheet, this terrestrial bridge existed until a rapid, 7,000-year transgression submerged the area, leaving the islands as isolated sentinels in the Arctic Ocean.

Geologically, the islands are complex, featuring a mix of Early Paleozoic sedimentary rocks and younger volcanic deposits. Bennett Island, the largest and highest at 426 metres, retains fragments of the small ice caps that formed during the frigid conditions of the Late Weichselian epoch, roughly 17,000 to 24,000 years ago. While the islands are now Russian territory, their history is marked by international intrigue. Discovered in 1881 by the ill-fated Jeannette Expedition, they became the subject of long-standing, though officially rejected, American territorial claims.

The search for the mythical Sannikov Land led explorer Baron Eduard Toll to these waters in the early 20th century, a journey that ended in his disappearance in 1902. Today, the islands remain a harsh, remote environment, administratively part of the Sakha Republic. Despite their isolation, they serve as a critical record of the Arctic's dramatic transformation from a vast, traversable plain to the submerged, ice-fringed geography that defines the modern East Siberian Sea.

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