Ice,
meet ice.

Greenland’s ice cap lands on East Antarctica, the Greenland coast between Ilulissat and Upernavik facing the plateau around Concordia and the coast of Wilkes Land. The Canadian Arctic islands land on the stretch of coast between Mawson and Mirny: Kugluktuk faces Mawson Station, Naujaat Mirny Station, Pangnirtung the country near Casey. Northern Alaska reaches Dronning Maud Land, where Utqiaġvik’s antipode lies on the ice 415 km from Russia’s Novolazarevskaya station.

The Antarctic Peninsula lands on Siberia, in Yakutia. Esperanza Base is 57 km from the antipode of Kysyl-Syr, and the stations on King George Island, among them Frei and King Sejong, all face the Vilyuy valley. The South Orkneys’ Orcadas Base faces Ust-Maya, on the Aldan.

The misses are the famous places. The South Pole’s antipode is the North Pole, in the Arctic Ocean 704 km from land. McMurdo faces the Greenland Sea off the north-east coast of Greenland; Vostok faces the Kane Basin between Greenland and Ellesmere Island, 12 km from land. Nuuk misses by 232 km, and Longyearbyen, on Svalbard, faces the Ross Sea.

Every Arctic town above 1,000 people in Greenland, Canada and Alaska, and the larger towns of the Russian and Norwegian Arctic, each listed if its other slice lands within 300 km of land. On the other side, every Antarctic research station that GeoNames gives a population, which leaves out abandoned bases and summer camps. Exact means land, or ice on land, opposite land at the place’s own point; where the other slice would get wet, the table gives the nearest spot from which an exact sandwich is possible.

No Arctic town is within a kilometre of a station’s antipode; the closest pairs are about thirty kilometres apart.

A sandwich’s elevation bonus is the height of one end plus the height of the other (Sandwich Law § 1.4). The Board scores it the way the map shows it: from the average height of the ground over cells about 20 km across, so every spot in a cell scores the same and you only need to be in the right cell, not on the summit. These are the corridor’s best cells, one per area, each with dry land at both ends.

1. +5,760 m437 km from Upernavik (Avannaata)cell average 2,840 m328 km from Concordia Stationcell average 2,920 m
2. +5,600 m570 km from Uummannaq (Avannaata)cell average 3,240 m659 km from Dumont d'Urville Station (French Southern Territories)cell average 2,360 m
3. +5,520 m873 km from Pond Inlet (Nunavut, Canada)cell average 1,720 m220 km from Kunlun Stationcell average 3,800 m
4. +5,360 m323 km from Pond Inlet (Nunavut, Canada)cell average 1,720 m425 km from Vostok Stationcell average 3,640 m
5. +5,280 m592 km from Upernavik (Avannaata)cell average 2,200 m336 km from Concordia Stationcell average 3,080 m

Both ends are ice caps: the best cell averages 2,840 m on the Greenland ice sheet and 2,920 m on the East Antarctic plateau, more than 300 km from the nearest station at either end. It is the highest pair outside the Andes corridors, behind only Vietnam and Peru and China and Argentina.

The window. Both slices must go down within five minutes of the same UTC instant (Sandwich Law § 2.1). The sandwich lobby holds you to it: when the first slice lands, the other side has five minutes.

The clocks. Agree the minute in UTC: stations keep time zones of their own choosing, often not the one their longitude suggests.

The light. Here the light makes its own rules. Two exactly opposite points are never in daylight together, and around the June and December solstices the sun never sets at one end and never rises at the other, so there is no moment when both are lit. Near the equinoxes it is the other way round: the sun skims the horizon at both ends for twenty minutes or more, twice a day.

The seasons. The Antarctic season, roughly November to February, is when stations are reachable and fully staffed; that is the Arctic winter, when the Greenland end is dark.

Nobody gets to either end by chance. The realistic Earth sandwich here is between two people already on the ice: a station member in Antarctica and someone in Greenland, Nunavut or northern Alaska. Sandwich Law counts ice sheets as expedition-class ground, and a sandwich poleward of 60° is legal and recorded, but ranked apart.

Then open an attempt in the sandwich lobby. It gives you a code and a link to send through whatever channel you already share, shows both slices when they arrive, and runs the five-minute window. Expedition rules apply before sandwich rules: go only where your station or guide says it is safe. The exact grade allows a kilometre of slack, which is usually enough to find somewhere you are allowed to stand.

No city above a million people is on this corridor.