An arch, yes, and much more

At 630 feet, St. Louis’ Gateway Arch is certainly an architecturalwonder. It’s the highest monument in the nation (by far) and the tallest arch in the world. Building it requiredworkers who were part engineer, partacrobat toiling at great heights over two-and-half years.

This Gateway to the West–which just turned 50–reminds us that, until relatively recently, the “frontier” lay just beyond the banks of the Mississippi River in Missouri. President Thomas Jefferson dispatched Lewis and Clark on...