The ancient, ruinous church of Sant Miquel de Martres in Caldes de Montbui,

The ruins of Sant Miquel de Martres church, first documented in 972 and included in the Inventari del Patrimoni Arquitectònic de Catalunya, are situated in Caldes de Montbui. It was originally sited on the ancient road connecting Caldes and Granollers, near the border of Caldes and Santa Eulàlia. Ervigi, who died in Jerusalem, made a testamentary donation to the church. By the early 18th century, the church was in ruins. Due to its proximity to the Coll de Baduell, it is often misnamed as Sant Miquel de Baduell. Today, the remaining structure stands as a historical relic amidst the modern town of Caldes de Montbui.

Sources: Wikipedia, OpenStreetMap, Wikidata