SAN DIEGO, CALIFORNIA—Using Lidar technology, ultra-high-resolution photography, and thermal imaging techniques, Mike Hess and Mike Yeager of the University of California, San Diego, created a 3-D digital model of the interior, exterior, and façade of the Baptistery of St. John, which sits in Florence’s Piazza del Duomo. “The point cloud data—taken from 80 Lidar scans—becomes the geometric scaffold for the high-resolution thermal imagery. The data can be projected into 3-D space so we know exactly what we’re looking at spatially. The drawings are spatially accurate and we can now pull a measurement for any part of the building we want to look at, down to the millimeter,” Yeager said in a University of California, San Diego press release. The construction of the Baptistery was completed in 1128 on the site of a Roman temple dating to the fourth or fifth century A.D. Yeager and Hess were joined by cultural heritage engineer Maurizio Seracini, Gianfranco Morelli of Geostudi Astier, and Vid Petrovic of IGERT-TEECH to examine an unexcavated area of the ancient site beneath the Baptistery with ground-penetrating radar. The team found what could be a staircase, two vaulted rooms, and a series of walls and hallways. “Now we’re able to use this technology to reference that data in space and ‘fly’ from the domed ceiling of the Baptistery down into the dirt to the ancient rooms beyond,” Yeager said. For more on how archaeologists use Lidar, read "Lasers in the Jungle."