Rolling Thunder parade rolls through Washington in honor of Memorial Day (PHOTOS)

The Rolling Thunder parade of motorcyclists, now in its 25th year, rolled through Washington, DC on Sunday, led by the parents of missing US serviceman Bowe Bergdahl. 

The annual Memorial Day weekend ride is held to raise awareness about prisoners of war and those missing in action, CNN International reported. 

26-year-old Bergdahl is an army sergeant from Idaho who was captured in Afghanistan in 2009 after he finished his guard shift at a combat outpost, according to CNN. 

"Bowe, your family has not forgotten you, your hometown has not forgotten you. Your state of Idaho has not forgotten you, and thanks to all of you here today, Washington DC has not forgotten you," his father, Robert Bergdahl, said in a speech at the ride, CNN reported. "We love you, we are proud of you. Stay strong, never give up. We pray for the day that we welcome you home." 

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The sergeant was captured by Taliban militants, and four videos of him have been released since, CNN reported. The last video was from February 2011, and it's unclear where Bergdahl is being held now. 

"We are still searching for him," said John Wagner, a spokesman for US Central Command, CNN reported. "We are actively looking for leads and information on his whereabouts and his condition."

Bergdahl is part of a proposed prisoner swap, in which the Obama administration would transfer five Taliban prisoners from Guantanamo Bay back to Afghanistan in exchange for American soldiers, the Associated Press reported. 

Motorcyclists participating in the Rolling Thunder parade wore yellow wristbands with Bergdahl’s name and the date he went missing on them, along with the traditional biker gear of leather vests and riding boots, though temperatures in Washington reached into the 90s, the AP reported. 

The Rolling Thunder ride goes through the American capital city over the Memorial bridge into the District, and makes its final lap from the Pentagon to the Lincoln Memorial, ABC News Channel 7 reported. CNN estimated that hundreds of thousands of motorcyclists participated in this year's memorial event; the AP estimated nearly one million riders would be in Washington for memorial day. 

"It's not just a bunch of people riding their bikes through DC," Peter Langer, who participated in this year's ride, told ABC News. "It symbolizes our freedom."

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