Founded in 1922, The Barnes Foundation is a must-visit for art lovers, housing one of the world's finest collections of impressionist, post-impressionist, and early modern art. The collection includes masterpieces by renowned artists like Renoir, Cézanne, Matisse, Picasso, and Van Gogh, along with remarkable African, Native American, and Pennsylvania German art. Beyond paintings, the Barnes also features decorative arts, metalwork, and furniture. Visitors can also explore the Foundation’s 12-acre arboretum, home to an impressive variety of rare plants.

Once the most famous prison in the world, having housed criminals like Al Capone, Eastern State Penitentiary is now a hauntingly immersive museum. Visitors can explore its eerie, abandoned hallways and learn about its revolutionary design and chilling history through guided or self-guided audio tours. During Halloween, the penitentiary hosts the famous "Terror Behind the Walls" event, where visitors may experience interactive scares.

More than 600,000 visitors — both Greek and foreign — flock here to witness the incredible natural spectacle, located 26km from the city centre. From July to September, butterflies swarm in their thousands, seeking cool and damp conditions. In the mornings, you'll see them clustered in hundreds on the branches.