[00:00.27]Almost two kilometers of green grass stretch from the front of 
[00:05.08]the U.S. Capitol building to the Washington Monument. 
[00:09.02]Thousands of people walk on it every day. 
[00:12.62]They also play games, have picnics, run their dogs and bike.
[00:17.48]The activities have damaged the expanse of land known as the National Mall. 
[00:23.39]Now workers are in the middle of a $45 million project to return thick, healthy grass to the area.
[00:32.01]"This thick blade, this thick, flat blade, is tall fescue."
[00:34.80]That is Michael Stachowicz. He is a man who knows his grass. 
[00:40.20]Stachowitz spent 20 years caring for golf courses. 
[00:44.23]Now, he manages one of the best-known green spaces in the world.
[00:49.23]"It is really cool to work on a piece of property that so many people around the world can relate to."
[00:57.50]More than twenty-five million people visit the Mall each year for concerts, 
[01:02.77]festivals and rallies, and, of course, to visit its popular museums. 
[01:08.07]Over the years all those feet have compressed the soil to the density of brick. 
[01:13.92]Only weeds can succeed in the rock-hard soil.
[01:18.35]The whole Mall is in a very poor condition. 
[01:22.39]But the repair project is rebuilding it, from the ground up. 
[01:26.70]The old soil will be replaced with new soil like you'd find under a professional baseball field.
[01:33.78]The workers are even improving the grass itself. 
[01:37.35]University researchers are helping to find the highest quality grasses for the space.
[01:43.88]"It being the most heavily trafficked piece of turf in the world, 
[01:48.29]we're trying to find the most traffic-resistant, the toughest turf that we can."
[01:51.65]Workers are also burying devices called cisterns that will capture nearly four million liters of rainwater. 
[02:00.03]Michael Stachowicz says they will help reduce pollution during heavy storms.
[02:06.07]Sometimes, storm waters flood waste sewers. 
[02:10.90]Then that water and the waste flow directly into the Potomac River, polluting it.
[02:16.96]The cisterns will help prevent that.
[02:19.86]The dig of such a huge stretch of ground has been a complex effort.
[02:26.25]"There's at least a century's worth of wiring, piping and tunneling underneath the Mall."
[02:31.54]The job of rebuilding the Mall is expected to be completed by early 2017.
[02:38.59]Hundreds of thousands of people will again walk all over it 
[02:43.39]to attend the presidential inauguration in front of the Capitol.
[02:47.94]I'm Jim Tedder.
[02:49.59]Words in This Story
[02:52.83]picnic 每 n. a meal that is eaten outdoors especially during a trip away from home
[03:00.36]manage 每 v. to have control of; to take care of and make decisions about
[03:07.10]yard 每 n. an outdoor area that is next to a house and is usually covered by grass
[03:15.24]compress 每 v. to press or squeeze (something) so that it is smaller or fills less space
[03:24.31]turf 每 n. the upper layer of ground that is made up of grass and plant roots