Beneath the east garage is the Strike Zone: a 15,000-square-foot children's area with a PlayStation Pavilion (proceeds benefit the Nationals' charity), a Build-A-Bear outlet, and other amusements.

The biggest scoreboard in baseball -- about five stories tall -- boasts a 4,532-square-foot high-definition video screen.

"We'd heard it would be $10 million or $20 million more than normal to build a LEED-certified park," says architect Joe Spear of HOK Sport, which designed the stadium with Devrouax + Purnell. "In the end, it was pretty affordable -- somewhere around $2 million more." Some upfront costs will be recouped; the state-of-the-art high-efficiency field lighting uses 21% less energy than conventional lighting.

The 6,317-square-foot green roof over a concession area is planted with about 1,200 drought-resistant sedums. A donation from the Chesapeake Bay Foundation covered the $100,000 cost.

The cherry trees, a special request by Nationals owner Mark Lerner, are a Washington icon. They'll bloom in early spring, just when baseball season gets under way.

The first-of-its-kind wastewater system uses sand filters calibrated to a ballpark's unique needs -- for instance, it's designed to screen out organic debris such as peanut shells and hot-dog bits. The engineers claim that water that has gone through the system is cleaner than the water in the nearby Anacostia River.

The Nationals' accountants think of the new stadium as a much greener ballpark than RFK, since it should significantly boost the team's bottom line. Luxury suites account for 15% of most teams' revenue; RFK had none. The new park has 66 suites, starting at $400,000 a year. Eight will be top-of-the-line Washington Suites with Wi-Fi, HDTV monitors, and seating for up to 29.

The site's design includes circles (the shape of the stadium) and triangles (the footprint of the Nationals' adjacent admin building) to echo the D.C. street grid created in 1791 by planner Pierre L'Enfant.

An in-house recycling center is equipped with four 34-cubic-yard dumpster-compactors, big enough to handle the glass, metal, and plastic recyclables generated during one three-day home stand.

The Nationals and the D.C. Sports & Entertainment Commission wanted a ballpark that was aesthetically "of the city." So for the sides facing the Capitol, the designers chose buff-colored stone typical of Washington's monumental architecture.

The 500 Presidential Seats right behind home plate are only available under "multiyear lease agreements." The first row runs $400 per seat, per game ($32,800 for the season); seats in the next nine rows are $300 ($24,600) -- more than twice the price of prime RFK real estate. But RFK didn't have a glass-walled lounge with views of the home batting cage and press-briefing room.

Up high, the prices come down low. About 400 seats in the Grandstand -- a fancy way of saying "nosebleeds," in sections 401 and 402 -- will go for $5 each on game days. Bonus: These seats face east, so the sun won't be in your eyes late in the day.