To be sure, the house that currently stands at 139 Elfreth’s Alley, estimated to be built as early as 1747, is listed for nearly eight times more than Philadelphia’s median home price ($160,700, according to Zillow) — and an analysis of the block’s recent sales suggests that obtaining the $1.2 million sale price could be difficult. In the last five years, eight of the 29 properties facing the block have been traded, with only one fetching more than $700,000. That property, 133-135 Elfreth’s Alley, which sold in 2017 for $790,000, was the largest on the block at 2,848 square feet.