As part of the Cadw Open Doors this year St Decumanus's Church, Rhoscrowther will be offering visitors free entry to explore.
This substantial church, nestling beneath the huge oil refinery, has been in the care of the Friends of Friendless Churches for thirteen years.
The refinery suffered a calamitous explosion in 1994 which shifted the roof of the church and led to the evacuation of the village.
This is a Grade I listed, largely medieval, church with an especially tall Pembrokeshire tower and a complicated ground plan which has four chapels, each built by the occupants of the four significant houses in the parish.
The interior retains medieval sculptures and effigy and a very fine Rococo monument.
The church will be open for visitors and will have short guides available for visitors to read in the church and to take home.
St Decumanus's Church
W: Click Here to Visit
10am until 4pm