The renovation of the National Shrine has been accompanied by another exquisite operation, namely, the construction of a crypt chapel in the basement where the much venerated tomb of the Apostle Thomas will indeed have a more worthy habitat.

The underground tomb Chapel at the Shrine treasures the remains of St.Thomas the Apostle of India. He died as a martyr for the noble cause of preaching the Good News in our country. We are proud and fortunate to be part of this Holy Land, which has been made sacred by the blood of St.Thomas. We have received the Christian faith because of the person and presence of St.Thomas.

The Shrine carries with it an international reputation of being erected over the tomb of one of the twelve apostles of Jesus Christ.

The underground tomb Chapel of St.Thomas has been built to enable pilgrims coming from different parts of the country and from all over the world to participate in group Eucharistic celebration, pray and venerate the relic of St.Thomas while the services are being held at the Shrine.

We wholeheartedly welcome you to come and pray at the tomb of St.Thomas to experience the divine touch, to be deepened in our Christian faith, to receive favours through the powerful intercession of St.Thomas, the Apostle of India and like him to bear witness to our faith by proclaiming that Jesus is Lord!

It is 72 feet long and 20 feet wide, and can accommodate 150 faithful at a time. A statue of St. Thomas in a lying state is installed over the tomb covered in glass, and over that a marble altar is erected. The basement extends itself to include the space behind the main altar of the Shrine to the northern end, in order to lend entrance to it from behind the church as well as to serve as a lobby. Access to the basement tomb chapel is through this lobby, which in turn contains two passages to the chapel on either side. The lobby itself is 50ft x 20ft and does have some venerable attractions to prepare one for a devotional visit to the chapel of the tomb. The basement chapel is indeed a boon to the devotees and pilgrims, as it provides them with a quiet atmosphere to spend time in prayer before the tomb of the saint.

The renovated Shrine and the Crypt Chapel added to it in the basement are indeed rare jewels in the crown of the Archdiocese of Madras-Mylapore.