Formentera is a Spanish island located in the Mediterranean Sea, which belongs to the Balearic Islands autonomous community (Spain) together with Mallorca, Menorca, and Ibiza.

A tombolo is a sandy or shingle isthmus. A tombolo, from the Italian tombolo, meaning 'pillow' or 'cushion', and sometimes translated incorrectly as ayre, is a deposition landform by which an island becomes attached to the mainland by a narrow piece of land such as a spit or bar. Once attached, the island is then known as a tied island.