WASHINGTON (ABC7) — It looks like a solid, well-made stone wall with a mysterious gap on 17th Street.
But it’s more than just a wall.
It's part of $4.5 million levee designed to keep downtown D.C. safe from flooding like the kind that Hurricane Florence could bring.
Nine-foot steel poles are inserted into pre-made foundations in the ground, then giant aluminum sheets are slid into place with a crane like a huge puzzle.
The National Park Service says the wall, designed by the U.S. Army Corps of Engineers, should be able to hold back any floodwaters.
The wall was first built in the 1930s, using sandbags and earthen fill.
Constructed in 2014, the new and improved version could face its first big test in the next couple of days.