Lima, meet
Cambodia.

Cambodia lands on central Peru. Lima faces the countryside of Pursat; Phnom Penh lands 6 km from Mucllo, in the Andes of Junín; Takeo near Perené, on the edge of the Amazon; and Siem Reap, the town of the Angkor temples, faces the south coast near Chincha Alta and Ica, whose own antipode is back near Siem Reap. The Mekong delta falls on the Peruvian Amazon: Ho Chi Minh City lands 44 km from Atalaya in Ucayali, Cần Thơ near Bolognesi.

Vietnam’s Central Highlands and coast fall on the southern Andes. Cusco faces the highlands of Gia Lai, 18 km from Chư Sê; Buôn Ma Thuột faces Cusco’s department; Qui Nhon lands near Corani in Puno; Huế and Da Nang in the department of Arequipa. Thailand’s far south reaches Peru’s north coast: Chiclayo lands 8 km from Khuan Don, near the Malaysian border.

Northern Vietnam and central Thailand miss. Hanoi faces the Pacific off northern Chile, 411 km from land, and Bangkok the Pacific 277 km off the Peruvian coast; Vientiane misses too. From Bangkok, the nearest exact spot is in Cambodia, facing Lima.

Every city in Vietnam above 300,000 people and Cambodia above 50,000, the larger cities of Laos and Thailand, and their capitals. On the other side, every Peruvian city above 100,000 and every regional capital, with the cities of Bolivia and western Brazil whose other slice lands in or off Vietnam, Cambodia, Laos, Thailand or Myanmar. Exact means land opposite land at the city’s own point; where the other slice would get wet, the table gives the nearest spot from which an exact sandwich is possible.

Five Peruvian towns have a twin in Cambodia or Vietnam: their centres are less than a kilometre from each other’s antipode, so bread in the middle of each is an exact Earth sandwich. One of them is the town of Asia, in the Lima region, 841 m from the antipode of Moung Ruessei in Battambang. Another is Mucllo, whose twin is Phnom Penh’s Ruessei Kaev district.

1. MuclloJunin⇄Ruessei KaevPhnom Penh, Cambodia579 m
2. TintaCuzco Department⇄K BangGia Lai651 m
3. SorasAyacucho⇄Siem PangStung Treng, Cambodia815 m
4. AsiaLima region⇄Moung RuesseiBattambang, Cambodia841 m
5. HuandoHuancavelica⇄Tăng KrâsăngKampong Thom, Cambodia847 m

Distances are between the centre points GeoNames gives for each town. Sandwich Law measures from where the bread actually lies, plus both phones’ GPS accuracy, so check your two spots on the map before the day.

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. +6,320 m18 km from Đắk Glei (Quang Ngai)cell average 1,560 m32 km from Orcopampa (Arequipa)cell average 4,760 m
2. +6,000 m5 km from Dak Cheung (Xékong, Laos)cell average 1,160 m14 km from Salamanca (Arequipa)cell average 4,840 m
3. +5,520 m20 km from Plei Kần (Quang Ngai)cell average 600 m45 km from Puyca (Arequipa)cell average 4,920 m
4. +5,520 m11 km from Măng Đen (Quang Ngai)cell average 1,160 m21 km from Coporaque (Cuzco Department)cell average 4,360 m
5. +5,440 m14 km from Vân Canh (Gia Lai)cell average 520 m18 km from Marcapata (Cuzco Department)cell average 4,920 m

This is the highest Earth sandwich on the planet, as the Board scores it. The best cell pairs the mountains of Kon Tum near Đắk Glei, at an average of 1,560 m, with the Andes near Orcopampa in Arequipa, at 4,760 m: +6,320 m in all, more than any other pair of cells on Earth with dry land at both ends. The second crosses into Laos. The Peruvian ends are above 4,000 m: plan for altitude and cold before anything else.

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. The simplest on any corridor: Vietnam, Cambodia, Laos and Thailand keep UTC+7, Peru keeps UTC−5, and nobody changes their clocks. Noon in Lima is midnight in Phnom Penh, every day of the year.

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 for about seven minutes: around six in the evening in Lima, which is around six in the morning in Phnom Penh.

The seasons. They work against you. The Peruvian Andes are dry from about May to September, just when the monsoon soaks Cambodia and southern Vietnam, whose own dry months run from about November to April. One of you will want a rain cover for the bread.

The geometry is the easy part; the hard part is a person at the other end, and the site does not match strangers. Write in Spanish and Khmer, or Spanish and Vietnamese, with your town and its antipode; plenty of Peruvian towns and Cambodian communes in the tables have active community pages.

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. Much of both sides is farmland, so put the bread on public ground, a roadside, a square or a park, or ask whoever owns the field. The exact grade allows a kilometre of slack, which is usually enough to find somewhere you are allowed to stand.

Ho Chi Minh City · Hanoi · Lima · Bangkok · Haiphong · Phnom Penh · Cần Thơ · Huế · Da Nang · Biên Hòa · Arequipa · Trujillo