>At 20th and Arch Streets, perched on the edge of a vast surface parking lot, sits a nearly 100-year-old Gulf gas station done up in Spanish terra-cotta trappings.
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>This vacant remnant of the early age of mass automobile ownership is protected by historic preservation regulations. It also stands in the way of the new 18-story office tower designed for insurance giant Chubb Ltd.
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>That’s why the 200-square-foot structure is going to be moved from its present location to the area around the Sedgley Porter House in Fairmount Park’s Lemon Hill section.

>“The structure will be preserved and, while placed in an ahistorical context, it’s going to remain publicly usable,” said Patrick Grossi, director of advocacy for the Preservation Alliance of Philadelphia.