An estimated quarter of a million bikers descended on the small South Dakota town of Sturgis in the largest mass gathering in the US since the start of the coronavirus outbreak.
They pressed ahead with the rally, which has been an annual event since 1938, despite fears that the gathering could trigger a Covid-19 outbreak not only among the bikers but also among the town’s population of just under 7,000.
Social distancing and masks were largely noticeable by their absence as the bikers started arriving en masse over the weekend.
Even Donald Trump’s description of mask-wearing as patriotic failed to convince the majority attending the rally.
Many made a point of bragging about their defiance of the guidelines issued by the Centres for Disease Control and Prevention, the US government health watchdog.
“Screw Covid. I went to Sturgis,” read one T-shirt which was on sale in the town.
With the bars expected to be packed and an array of concerts staged over the 10 days, health experts fear the rally could turn into a super-spreading event.
Officials in Sturgis have stepped up precautions, including planning mass testing of residents.
Local bars, like the Side Hack Saloon, did try to minimise the risk by spacing out tables and making hand sanitiser available.
Bob Graham, 71, who was making his 36th trip to Sturgis, was one of the few to wear a mask for the visit which he describes as annual therapy for himself and his wife.
"We don't want the virus. We want to come up here a few more years yet.”
Kristi Noem, South Dakota’s Republican governor, has taken a more relaxed approach towards the coronavirus pandemic than her counterparts in other states.
Neither masks nor social distancing were required when Mr Trump held a celebration at Mount Rushmore at the start of the month.
However, the Cheyenne River Reservation has taken a far stronger line, because of the higher incidence of Coronavirus among native Americans.
The Oglala Sioux, which has recorded more than 160 Covid cases and two deaths, mounted checkpoints only allowing people to pass through the reservation if they passed a coronavirus screening questionnaire.