Saint Alexander's Cathedral is the seat of the Diocese of Marbel and the spiritual centre of Catholic life in South Cotabato. The cathedral anchors the city's main plaza, and the surrounding square fills with vendors and families on weekend afternoons. The interior is straightforward rather than ornate, but the cathedral is notable for being part of a diocese that actively engages with the indigenous B'laan and T'boli communities — the bishop's office has long worked alongside tribal leaders on land rights and cultural preservation.
Mass is held daily, and the cathedral courtyard is a pleasant place to sit in the early evening when the heat drops.