The modernization of Mount Vernon is slated to take a significant step this week as supporters of the first presidential estate break ground for an underground museum and education center. The $85 million project includes two theaters that will show a Hollywood-style film about George Washington, a multimedia presentation of the crossing of the Delaware River that includes snow falling on visitors, and new displays for the rhinestone shoe buckles he wore at his inauguration, his ceremonial sword and his famous false teeth.

The fundraising campaign has already yielded $75 million in pledges (with $40 million in hand), said Jim Rees, executive director of the Mount Vernon Estate & Gardens. Rees said the new additions, designed in the aftermath of the terrorist attacks of Sept. 11, 2001, have not prompted increased security measures. The house and grounds have always been monitored by security cameras and uniformed armed guards.

"We keep in touch with the local FBI people and they have consistently told us we are not in the same category as the White House and Capitol. We do know where we could have magnetometers, if needed," said Rees. "But our entry experience is so beautiful, we don't want to frisk the visitors."

Attendance at Mount Vernon slipped dramatically after the terrorist attacks. But, matching the experience of other Washington destinations, the numbers are rebounding this year. "Last year we were under 800,000 for the first time since 1955," Rees said. "If we keep at the pace we have had so far this year, we will be at 950,000."

Part of the surge is attributed to the opening of the National World War II Memorial, which is attracting a large number of visitors likely to include Mount Vernon on their itineraries. "The World War II site has helped with an older, more conservative, more history-minded visitor," said Rees.

The new features are aimed at raising awareness about many aspects of Washington's life, especially among young people, and to compensate for the shortcomings of the displays at the mansion, which are limited to what the president had at the home. The house and grounds are owned by the Mount Vernon Ladies' Association, a private organization.

Hidden from the main mansion by trees, the improvements will include a connecting museum and education center and a separate orientation center. The project covers 66,700 square feet, with 65 percent of it underground. The new facilities are scheduled to open by the end of 2006.

The main feature of the orientation center will be a 15-to-20-minute film that will emphasize Washington's youthful military and physical heroics. Originally, Rees talked to a number of production companies, one of which included director Steven Spielberg, but those negotiations didn't work out. "We never got far," Rees said.

Ron Maxwell, whose best-known historical works are "Gods and Generals" and "Gettysburg," each clocking in at about four hours, was recruited to show Washington the action hero. "The film will emphasize his youth, his adventurousness, his willingness to take physical risks. We see someone who is learning, daring and learning from his mistakes, and that shapes him," Maxwell said. "The image will be startling because most of us are used to, unless we are scholars, the guy in the powdered wig, the marble man. We see a monument that is not human."

Rees said, "Ron has the reputation for being incredibly detailed and serious about the historic context." Maxwell said yesterday that casting has not been completed, though filming on the $2.5 million movie is expected to start late this summer.

In another theater in the education center, visitors will learn about the Revolutionary War in a multimedia presentation about the battles in Boston, Trenton and Yorktown. When Washington crosses the Delaware River in the dead of winter, Rees promises snow will fall on visitors. "It will be what younger people hope to find," he said.

In total, the museum and center will have 23 theaters and galleries, with one devoted to Washington's views on slavery (he ordered in his will that his slaves be freed when Martha Washington died), another highlighting the first couple's 40-year romance and another on the Constitutional Convention.

To enhance the view of Washington as a farmer, military leader and statesman, the museum will have three life-size figures of him at ages 19, 45 and 57 that will be based on technology being developed by a forensic scientist, Jeffrey Schwartz.

The museum will house many familiar items associated with the president. The Jean Antoine Houdon bust, which has been restored, will be displayed. Personal belongings, including silver and ceramics, his gold watch and his globe, will have new settings. The Metropolitan Museum of Art will lend four famous paintings of Washington by James Peale, Rembrandt Peale, Louis Remy Mignot and Thomas Rossiter. A couple of paintings of the president by Gilbert Stuart, which have been in the administration building and out of public view for years, will be displayed in the museum.

The project also will give the first president something he never had: a presidential library. The library will provide online access to all of Washington's papers, including 40,000 letters, as well as duplicates of many of the 900 books he owned. "We want to be the place to start in a study of George Washington," Rees said.

On Friday, officials, donors and Washington descendants will plant a 30-foot-tall red maple, the first of 200 well-developed trees to be planted throughout the grounds. To give the site an added dash of authenticity, the roof of the new center will be a pasture for Hogg Island sheep, the same species raised by Washington.

Visitors to Mount Vernon's new museum and education center will be greeted by a bust of Washington whose eyes will appear to follow them.An exhibit on the French and Indian War will re-create a Pennsylvania woods where a key battle occurred.