Simplify the following text for a Grade 6 native English-speaking person.
Original: The main difference between Bramante 's design and that of the Pantheon is that where the dome of the Pantheon is supported by a continuous wall , that of the new basilica was to be supported only on four large piers .
Simplified: Bramante 's dome was to be like the one on the Pantheon . But there was one very big difference between the Pantheon dome and Bramante 's design .