Geoffrey Rolat, 65, has been visiting for decades with his father, Sigmund A. Rolat, who was born on July 1, 1930, in Czestochowa, Poland.

The elder Mr. Rolat survived the death camps and became a prominent philanthropist; he is one of the main donors to the POLIN museum.

This year, the son gathered with other bike riders at dawn at the community center in Krakow, waiting for a bus to Auschwitz, where they would begin the ride. A man stood at the gates of the center, rambling incoherently about Jews and “his country.”

“You have crazy people everywhere,” Mr. Rolat said, nonplused. “I truly believe the safest place for a Jew today in Europe is in Poland.”

As the bikers rode through small towns and villages, past churches and statues of the Virgin Mary, there were no cross looks or unkind words from people tending the fields along the way. There were mostly waves and smiles, and the occasional curious glance at the pack of riders, outfitted in bike jerseys emblazoned with the Star of David.

As the riders approached Krakow, they were met by small crowds cheering them on.

“To ride from this place of devastation to this place of the living is remarkable,” Mr. Rolat said.