St Lawrence is one of the most widely venerated saints of the Roman Catholic Church. Devotion to him was widespread by the 4th century.
St Lawrence is especially honored in the city of Rome, where he is one of the city's patrons. There are several churches in Rome dedicated to him, including San Lorenzo in Panisperna, traditionally identified as the place of his execution. The picture above is of the stone where St. Lawrence was laid after his death.
Here's the shrine in Rome containing the gridiron said to have been used to grill Saint Lawrence to death.
St. Lawrence, pray for us,
that the flames of Divine love may burn away all traces of vice within us,
and that we may be practical and zealous in the service of the poor.
(Info. to Catholic Encyclopedia)