Railroad trestle

Lucin Cutoff railroad tresle over Salt Lake. Over 23 miles long in the water, it was the engineering wonder of its time.

from Wikipedia:

"The Lucin Cutoff is a railroad line which included a railroad trestle which crossed the Great Salt Lake in Utah. Built by the Southern Pacific Company between February 1902 and March 1904...By going west across the lake from Ogden, Utah to Lucin, Utah, it cut off 43 miles and avoided sharp curvatures and grades. The trestle was eventually replaced in the late 1950s with a parallel causeway..."

I learned that the causeway is earthen and it divided Salt Lake into two halves — one half is now saltier than the other. So if you want the full Salt Lake experience, go to the northern half.