An arch site is a structure that consists of an arch, which is a curved structure that supports weight. The term 'arch site' can refer to a variety of structures, including bridges, aqueducts, and monuments. In this crossword, the solutions INSTEP (6 letters), FOOT (4 letters), and PARIS (5 letters) all refer to arch sites. The INSTEP solution refers to the Pont du Gard, an ancient Roman aqueduct in France. The FOOT solution refers to the Arc de Triomphe in Paris, France. Finally, the PARIS solution refers to the Eiffel Tower, also located in Paris, France.