'Fight for Air' climbers run up over 40 flights of stairs at Salesforce Tower in Indianapolis | LIVE

Paris Olympics: Tourists test their endurance by climbing Eiffel Tower

East TN first responders honor fallen heroes at Knoxville 9/11 Memorial Stair Climb

Tennessee ROTC cadets climb the stairs at Neyland to honor the memory of 9/11 victims

UT Army, Air Force ROTC honors lives lost in 9/11 with stair climb in Neyland Stadium

Hundreds of military members in training do stair climb to honor the first responders who saved live

Annual memorial stair climb for lost lives held on Sunday

Stairclimb raises awareness for blood cancer

UT ROTC cadets honor the fallen on 9/11 with stair climb at Neyland Stadium

Memorial Stair Climb honors hundreds of firefighters who died in the Sept. 11 attacks

Washing Commanders participate in Knapp Stair Climb to raise awareness of distracted driving

Firefighters participate in Morristown Landing's 9/11 Memorial Challenge

24 years since 9/11 attacks: Communities across the country honor the lives lost

Red Rocks hosts annual 9/11 stair climb honoring fallen firefighters

East Tennesseans take part in Knoxville's 9/11 memorial stair climb at Smokies Stadium

Firefighters in Tampa hold memorial stair climb in honor of 9/11 victims

Honoring first responders with the 9/11 Memorial Stair Climb

Hundreds of people gather for Fight For Air Climb in Tampa

Firefighters gather in downtown Denver for 9/11 memorial stair climb

9/11 stair climb events honor fallen firefighters

Fight for Air Climb: Tampa woman uses aerial arts to raise awareness for lung disease research

110 stories: Colorado firefighters honor those lost on 9/11 attacks with stair climb

Spartan Race participants put their endurance to the test at Raymond James Stadium

Out & About in East TN: TN Valley Fair, Ripley's Believe it or Not and 9/11 memorial stair climb