The symposium, “Against Gravity: Building Practices in the Pre-Industrial World,” will gather specialists to examine building practices in the pre-industrial world, with an emphasis on Greek, Roman, Byzantine, medieval, and pre-modern Islamic architecture. Building practices will be considered in a variety of ways: examining regional and local trends, considering specific architectonic forms, practices of construction, cultural interaction, and wider considerations of the built landscape and change. March 20, 9 a.m.-3:15 p.m. at Rainey Auditorium, Penn Museum, 3260 South St., and 3:30 p.m.–5:15 p.m., 419 Fisher-Bennett Hall, 3340 Walnut St.; March 21 and 22, Widener Auditorium, Penn Museum. Info: www.sas.upenn.edu/ancient/againstgravity.html. Registration: www.eventbrite.com/e/against-gravity-building-practices-in-the-pre-industrial-world-tickets-15797448594. The symposium is free and open to the public.