The narrows is a several mile long section of Zion where two adjacent cliffs narrow are so close together that the Virgin river pretty much fills the bottom. It is pretty shallow (ankle to knee deep) and people hike in the river. With the canyon walls towering on both sides 1200+ feet, it is supposed to be an incredible experience.
In hindsight I wished we would have brought or rented proper gear to do the narrows. I assumed it would be too cold but it was around 80 and the water felt good. Alas, we had to stop at the start of the narrows since we did not want to soak our hiking boots.
"We're only smiling because you promised us ice-cream when we get back"