A temple to “all the gods”, rebuilt on the orders of the emperor Hadrian
around 126 AD in the Campus Martius in Rome, over the foundations of an
earlier temple built by Marcus Vipsanius Agrippa, whose name is still
carved across the front. Its 43-metre concrete dome was the largest in
the world for 1,300 years, until Brunelleschi’s in Florence. The nine
metre oculus at the top is still the only source of daylight, and the
rain comes in through it too.
