Thiruvithamcode Arappally, or Thomayar Kovil or St. Mary's Orthodox Church, is a church located in Thiruvithamcode in Kanyakumari District, Tamil Nadu state in India. It is believed by the Christian communities in Kerala that the historic Thiruvithamcode Arappally, also called Amalagiri church as named by the Chera King Uthiyan Cheralathan, was built by St. Thomas, known as the Apostle of India, in 63 AD. It is believed to be the world's oldest existing church structure, and is now declared an international St. Thomas pilgrim center.