WASHINGTON — It's been a long six years.

But after intense renovations that left it closed to the public, the historic building that houses the Smithsonian's National Portrait Gallery and American Art Museum is speeding toward its July 1 reopening.

Recently a crane lifted a crate containing two large scale paintings to the building's second floor. It contained the 10-by-16-foot "Grant and His Generals" by Ole Peter Hansen Balling, and the 22-by-5-foot "Achelous and Hercules" by Thomas Hart Benton.

Their arrival was a sign that the $216 million overhaul, which began in January 2000, is almost complete. New features in the 19th-century building include original-style plaster and tiles, an additional 60,000 square feet of gallery space, more than 50 new artworks and a glass-enclosed atrium, which won't be finished until later in the year.

For the first time in the museum's history, ultraviolet-light filters in the glass will allow officials to remove walls that covered ornate windows. The windows will let controlled natural light into the galleries, eliminating a tomblike feel, said Eleanor Harvey, chief curator for the American Art Museum.

"So now the public can enjoy works in daylight that were painted in daylight," Harvey said. "It is like a freshly refurbished old friendship."

Harvey said officials have had to be a lot more creative with displays — for instance, converting offices into galleries to create more room for art.

Right now, it's hard to believe that the empty, unfinished halls are part of what will again be a top tourist destination. When the throngs arrive after the opening, a new floor plan will allow for a "seamless walk" through both museums.

The landmark was the third public building constructed in Washington, after the U.S. Capitol and the White House. It housed President Abraham Lincoln's second inaugural ball and was used as a barracks during the Civil War.

While they were closed, the museums sent many of their exhibits on tour, and now they're finally "coming home," Harvey said. Some old favorites are the National Portrait Gallery's presidential portraits — the only complete collection outside the White House; and the American Art Museum's Georgia O'Keeffe and Edward Hopper paintings.

The museums will also feature the new Lunder Conservation Center, the first permanent conservation facility that allows the public to view behind-the-scenes art-preservation work.

But there is a downside to the renovations, Harvey said. After being closed for six years, the museums now have to re-establish their identities with the public.

"When we closed, there was a general feeling of shock and dismay," Harvey said. "But people will be pleased with what has happened. I'm looking forward to watching this sleeping giant wake up."