The 90-foot Roman masonry marvel that defies gravity
In 1915, the Penn Museum unveiled a structural masterpiece: a 90-foot high rotunda. Using an ancient Roman technique, architects created a pillar-free space so strong it supports the massive floor of the room above it, all while housing a world-renowned collection of Chinese art.
The Harrison Rotunda at the Penn Museum is more than an architectural landmark; it is a feat of engineering known as the Guastavino vaulting system. Completed in 1915, this system utilizes an ancient Roman masonry technique to create a dramatic domed ceiling centered by a bronze starburst. At its opening, the Harrison Auditorium featured the largest floor dome of its kind in the world, uniquely engineered to support not only its own weight but also the floor of the Chinese Rotunda situated directly above it.
The structural design reflects a period of intense architectural experimentation and a commitment to the University's long-term museum master plan. This plan was intended to allow for the infinite expansion of collections as they grew. The auditorium itself has served as a cultural hub for over a century, hosting significant figures such as Margaret Thatcher, Jane Goodall, and Colin Powell, as well as pivotal university milestones like Penn Medicine Match Day and various graduations.
As the museum celebrates the 100th anniversary of this space, it is entering a new era of transformation. A major renovation is underway to modernize the historic site for the 21st century. While the museum aims to preserve the architectural integrity of the space—including the refurbishment of Art Deco seats installed in the 1940s—the project will focus heavily on accessibility. Planned upgrades include new elevators, wheelchair accommodations, and improved audio-visual equipment, ensuring the historic hall remains a functional venue for K-12 programming and public lectures for generations to come.
Source: The 100th Anniversary of the Harrison Rotunda at the Penn Museum
