America’s other
side is ocean.

The three islands are French and Australian territory, and nobody lives on them for good. Kerguelen and Amsterdam have French research stations, Port-aux-Français and Martin-de-Viviès; Heard Island, Australian, has nobody at all. Their twins are prairie and ranch land. Kerguelen’s fills the country where Saskatchewan, Alberta and Montana meet: Port-aux-Français’s antipode is 66 km from Maple Creek. Heard Island’s lies in the farmland near Shellbrook, west of Prince Albert. Amsterdam Island and its neighbour St Paul are specks, and so are their twins, in eastern Colorado near Lamar and Cheyenne Wells.

Everything else misses. New York, Chicago, Los Angeles, Toronto and Montréal all face the open Indian Ocean, a thousand kilometres or more from land; their nearest exact spots are the Colorado and prairie twins. Calgary comes closest of the big cities, a sloppy sandwich 198 km short of Kerguelen; Medicine Hat is a deli one, 16 km short. Bermuda is a deli sandwich too, 37 km off the coast of Western Australia, south of Perth.

The other exceptions have their own guides: Hawaii faces Botswana, and the north of Alaska and the Canadian Arctic face Antarctica.

Every city of a million people in the United States and Canada, and every provincial capital, with the towns of the northern Great Plains above 20,000 and the smaller towns close to the three twins; each listed if its other slice lands within 200 km of land, or it is a capital or a city of a million. On the other side, the research stations of Kerguelen, Heard and Amsterdam, and Perth. Exact means 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.

With no towns on the islands, there are no twins. The station at Amsterdam Island comes closest: its antipode is 37 km from Lamar.

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. +1,520 m52 km from Dunmore (Alberta, Canada)cell average 1,160 m55 km from Port-aux-Français (Kerguelen)cell average 360 m
2. +1,440 m44 km from Chester (Montana)cell average 1,320 m108 km from Port-aux-Français (Kerguelen)cell average 120 m
3. +1,120 m15 km from Shellbrook (Saskatchewan, Canada)cell average 520 m16 km from Spit Base (Heard Island and McDonald Islands)cell average 600 m
4. +1,040 m69 km from Maple Creek (Saskatchewan, Canada)cell average 1,000 m8 km from Port-aux-Français (Kerguelen)cell average 40 m

The best cell pairs the Cypress Hills country of south-eastern Alberta, at an average of 1,160 m, with the west of Kerguelen.

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. Kerguelen and Amsterdam keep UTC+5 all year. Colorado and Montana keep Mountain Time, 12 hours behind in winter and 11 in summer; Saskatchewan keeps UTC−6 all year, 11 hours behind.

The light. Two exactly opposite points are never in daylight together: sunrise at one end is sunset at the other. The atmosphere bends a little sunlight over the horizon, so twice a day, on a clear flat horizon, the sun is up at both ends at once for nine to thirteen minutes at these latitudes. Put the bread down then and both photographs get golden light, one at dusk and one at dawn.

The seasons. Opposite, and harsh at both ends: a prairie winter at one end is a sub-Antarctic winter at the other, and the islands are windy all year.

The hard part here is not a partner but a berth. Kerguelen and Amsterdam are reached by the French supply ship from Réunion a few times a year, and its places go mostly to station staff and scientists. The realistic sandwich is someone already posted to a station, with a friend on the prairie or in eastern Colorado at the right minute.

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. The prairie end is ranch and farm land, so put the bread on public ground, a roadside or a town park, or ask the owner. The exact grade allows a kilometre of slack, which is usually enough to find somewhere you are allowed to stand.

New York City · Los Angeles · Toronto · Chicago · Perth · Houston · Montréal · Phoenix · Philadelphia · San Antonio · San Diego · Dallas · Calgary · Ottawa · Edmonton · Jacksonville · Fort Worth