I was spinning in a circle at 30 miles per hour over the Mississippi River when I noticed the bus.

It looked like it was driving in slow motion across the Hennepin Avenue bridge. Who is on it? Can they see me?

The brain takes peculiar snapshots in the 30 seconds it has to process jetting through midair on a zipline — like bridges in the distance, and sunshine gleaming off a thawed river. But the apprehension that weakened my knees on the scaffolding moments before washed away, replaced by a screaming pulley system above my head that seemed to be yelling, "Here we go!"

Friday was Day 1 of the Bold North Zip Line, a straight shot from Nicollet Island to West River Road held in conjunction with the Super Bowl. Expect to see a lot of it between now and the Big Game; spokesman Kevin Smith said 10,000 tickets have been sold and TV inquiries have poured in from NBC Nightly News, the Ellen Show and CNN.

I wasn't sure what to expect, as a zipline neophyte.

My fellow zippers (we rode in a pack of four) boasted beforehand about cruising through South Africa and Hawaii tethered to a cord. I had only some vague memory of holding a bar gliding through the air as a child.

It turns out the toughest part is the ascent.

After signing away liability for "loss, damage, expense or injury including death that I may suffer" and getting fitted into my harness, we began climbing the 10-story scaffold to the launch point. My heart began to race as I considered the stability of the narrow 100-foot structure plopped in a parking lot.

Just how much engineering goes into a tower seemingly held together by metal rods? I hoped a lot.

"Looks pretty sturdy," remarked my colleague Tom Horgen.

At the top platform, we watched as the group before us slowly edged out onto what Smith calls the "steps to nowhere," before shoving off across the river. An array of helpers then strapped us in and guided us down the steps.

I did not look down.

Suddenly I was speeding toward downtown, turning at the whim of the wind and my straps. The water, the bridge, the launch site, colleagues shooting videos, the bus, the Post Office, the landing pad — the mind struggles to keep up with it all. Half a minute later we settled back on solid ground on wobbly legs.

Not a bad day at the office.