America's oldest continuously operating brewery has been located here since 1831, two years after its founding. Its centerpiece is a five-story brew house, a remarkable survival from the first days of the American brewing industry. Large windows on the third and fourth stories have replaced the louvered panels that facilitated the cooling process. The turn-of-the-twentieth-century additions to the complex are among the dozens of Pennsylvania brewery buildings designed by Philadelphia architects Otto Wolf and Clarence Wunder. Across Mahantongo Street, quirky terra-cotta friezes set into curved gables announce the former Yuengling Ice Cream and Dairy Plant, designed by another Philadelphia industrial architect, Amos W. Barnes. It was constructed in 1919 with Prohibition looming. Much of Yuengling's brewing capacity has moved away from Mahantongo Street, but the original brewery complex continues to be the focus of visitors’ interest. At 606 Mahantongo Street is the simple Italianate twin house (1870) that was built by a member of the Yuengling family and later became the home of novelist John O’Hara's family.