Church of Nuestra Señora del Rosario de La Unión Monument · La Unión, Campo de Cartagena, Murcia Image of La Unión, not of the place itself. A church built in 1902 and known as 'the cathedral of the mining sierra', home to the patron saint of La Unión and the venerated Cristo de los Mineros; declared a Bien de Interés Cultural (Spain's highest level of heritage protection). Photo: Flamanim (CC BY-SA 4.0) What to see and do in La Unión