With eleven Tagus crossings already behind us, the road back begins. This chapter runs from Abrantes to Santarém: Almourol Castle, perched on its rocky island and the ultimate symbol of the Templars in Portugal; Golegã, the country's "horse capital"; the Chamusca Iron Bridge, a textbook example of early-20th-century ironwork; and the D. Luís I Bridge in Santarém, once the largest bridge on the Iberian Peninsula.

The most intense day of the whole trip: crossing into Spain and back over a dissolving border, riding through gorges carved by the Tagus, spotting vultures over sheer cliffs, and hugging a 3,350-year-old olive tree — the oldest in Portugal. Five bridges, one unforgettable day, ending in Abrantes.