An arrow on a signpost points down through the earth to a distant city, the city's name and straight-line distance printed on the side of the arrow. In the arrow's tail a widefield eyepiece provides a view of the far-surface of the planet, as if the Earth were hollow & translucent and you could peer through an opening in it. Continents and oceans are perceived in accurate spatial relationship to your location with the distant city centered in the field of view. Companion installations in sister cities?