Former U.S. Vice presidential candidate and Alaska Governor Sarah Palin (R) greets some of the thousands of motorcycle enthusiasts and military veterans participating in 'Rolling Thunder' rally May 29, 2011 in Arlington, Virginia. Although not an official guest, former U.S. Vice presidential candidate and Alaska governor Sarah Palin is expected to participate in today's motorcycle parade from the Pentagon to the National Mall.

People watch as an acrobat rides his motorcycle around a circular track at an entertainment park set up outside a shrine in Rawalpindi, Pakistan, on June 19, 2013. (Photo by Muhammed Muheisen/Associated Press)

Motorcycle fans dressed as Santa Claus ride near Charlottenburg Palace (Schloss Charlottenburg)during the 25th annual “Santa Claus On Road” Berlin Bike Tour, to deliver gifts to the needy on December 10, 2022 in Berlin, Germany. Some 200 riders with vehicles decorated with lights and mini-Christmas trees took part in the annual event on its 25 year. Anyone may ride along, whether on motorcycle, trike or quad, as long as the vehicle is decorated accordingly. (Photo by Omer Messinger/Getty Images)

Partipants vie for the ball during the 11th Mud Olympics held at the North Sea coast in Brunsbuettel, Germany, July 11, 2015. Amateur athletes have competed in several disciplines at the Mud Olympics since 2004. (Photo by Axel Heimken/EPA)

Indian soldiers practice their stunts on Royal Enfield motorcycles in preparation for the upcoming Republic Day parade on January 11, 2012 in New Delhi, India. (Photo by Daniel Berehulak /Getty Images)

A dog wears fake eyes while riding a motorcycle in Samut Sakhon, Thailand June 23, 2016. (Photo by Jorge Silva/Reuters)

Festival goer practice yoga during the O.Z.O.R.A. festival on August 4, 2016 in Tolna, Hungary. Ozora is a village in Tolna County. In recent times it has become famous for the O.Z.O.R.A. psychedelic trance festival which has been held on an estate in Ozora near small village Dadpuszta every year since 2004. The first party was called Solipse and took place during the Solar eclipse of August 11, 1999. (Photo by Mohai Balázs/MTI/MTVA)

A model poses on Aprilia motorcycle displayed at the Indian Auto Expo in Greater Noida, on the outskirts of New Delhi, India, February 4, 2016. (Photo by Anindito Mukherjee/Reuters)