Inside a plain-looking farmhouse building is a domed hall from the fourth century, its cupola covered in mosaics of hunting scenes, biblical stories and figures that may represent the imperial family. Some scholars believe it was built as a mausoleum for Constans, son of Constantine the Great, who was killed in 350; others are not so sure, and the debate is part of the fun. The site belongs to the UNESCO listing for the Roman town of Tarraco.
Tarragona, the old Tarraco, capital of a huge Roman province, lies only a few kilometres away, with its amphitheatre by the sea, the circus vaults under the old town, the walls, and the Pont del Diable aqueduct in the hills to the north. Centcelles makes a quiet counterpoint to all that grandeur: you may well have the dome to yourself, with only birds outside and the distant hum of traffic.
The immediate landscape is not glamorous. The Camp de Tarragona plain around Constantí and La Pobla de Mafumet is a mix of hazelnut and olive groves, industrial estates, motorway junctions and the large petrochemical complex that dominates the skyline to the south. But the riding gets good fast once you head inland: the roads up into the Prades mountains, toward Alcover, Mont-ral and the Serra de la Mussara, climb through pine forest with tight hairpins and views back over the coast. Summers here are hot and humid, so morning or late afternoon riding is kinder, and the Mediterranean wind can kick up in the afternoons.
Constantí is a town of over five thousand with fuel, shops and simple bars where you can order a coffee and a bocadillo. For a proper lunch, Tarragona's Serrallo fishing quarter serves seafood and rice dishes by the harbour, while Reus, a short ride west, is the birthplace of Antoni Gaudí and the home of vermouth, which locals take as an aperitif before lunch with olives and anchovies.