Throngs of clean energy activists jammed a major thoroughfare in a mile-long march from city hall to Independence Mall, near the Liberty Bell. They held anti-fracking and anti-pipeline signs, some with illustrations such as a train surrounded by a fireball and the words "No Exploding Trains". Others held "Bernie or Bust" signs.
Sam Miller, 82, had traveled from Erie, Pennsylvania, to join the march that stretched several blocks and across a wide street as temperatures in the city soared into the mid-90s. He said he was inspired because "fracking is invading Mother Earth".
As in Cleveland around the Republican convention this week, police were using bicycles as barricades and volunteers were handing out water to marchers. Shoppers came out of stores to watch the march.
Chants of "Bernie! Bernie!" were met by counter echoes of "Hillary! Hillary!"