Here's the church of Sant' Agnese in Agone,
in the Piazza Navona; its main
architect was Borromini, arch-rival of
Bernini, who created the Four Rivers fountain
(built around an obelisk brought to Rome
by the emperor Caracalla) directly in front of the church.
It's said that Bernini sculpted his figure depicting
the Nile with its head covered, as though
hiding from Borromini's looming church façade,
but in fact the fountain predates the
façade by quite a few years.
[To see more churches from around the world, go here.]