The basilica of St Peter in Rome attracts catholic pilgrims from all over the world. The church dates back to the 2nd century A.D., when a first building was erected over the grave of the apostle Peter. The first basilica was built in 349 by emperor Constantin. Construction of the actual church was started in 1506 by pope Julius II and took over 100 years to complete. The spectacular 136 m large cupola is based on a design by Michelangelo.