Germantown Avenue in Philadelphia, in particular its upper reaches through Germantown, Mount Airy and Chestnut Hill, is notable for being paved with Belgian blocks; repaving projects on this thoroughfare have retained or reintroduced block paving to give additional historic character to these neighborhoods. Part of this character includes the tracks of the 23 trolley, though the modern tracks are encased in concrete slabs rather than blocks, and the trolley line itself is currently operated by buses.