Sue starts her journey in the Mexican city of Tijuana, at the western end of the border; on a night out with Matthew she tries just about every sample in a Tequila showroom and is left in no doubt the city deserves its reputation as a party town.

Sue is half-way along the border in the city of Juarez; Juarez is one half of a super-city, adjoining El Paso in Texas, but divided by the border; it's also separated by a 57-mile section of border wall, but people come and go across it every day.