The U.S. National Arboretum is on a 180-hectare plot of land in the eastern part of Washington, several kilometers from the center of the city. Here nature's beauty is brilliantly on display. Thanks to the careful attention of the park's skilled landscapers and botanists, the Arboretum provides the perfect escape from the frantic pace of the capital.

The fish pond is a favorite spot for visitors.

Sam Augusta has brought his one-year-old son to play by the water.

"We like to come and take a look at the fish, and the lotus flowers and a lot of the plants. He's never seen the fish up close like this before."

Joan Love is a regular visitor. She says she knows almost every plant on display and sees animals you would never expect to see in a big city.

"I mean there's so much to see here and so much to do here. But one thing is, you don't even know you're in Washington DC. I mean, you're just here, in all this wonderfulness."

Of course, being in Washington, it is perhaps fitting that the arboretum also has what was once, literally, part of the nation's Capitol.

These columns are carved from Virginia sandstone and once stood at the eastern entrance to the Capitol building. They witnessed the inauguration of U.S. presidents from Thomas Jefferson to Dwight Eisenhower. When the Capitol was renovated in 1958, they were replaced by marble columns, and the Arboretum acquired the old columns.

In addition to providing a place to relax, the Arboretum has another purpose as well.

Thomas Elias is director of the Arboretum.

"The National Arboretum was established in 1927 by an act of Congress as a research and educational facility, devoted to studying plants, and disseminating information to the American public."

Each year the Arboretum sends scientists to collect plant specimens from around the world. They are brought back to the park and planted, where they are used to research ways to breed disease- and insect-resistant plant species.

Arboretum officials are also quick to show a special exhibition of vegetation used to produce bio-fuels.

"It's to demonstrate to people and show people what the plants that can be used to generate bio-fuel or ethanol as a substitute for fuel. So we selected 21 different plants that can be used in some way to generate fuel."

There are algae, alfalfa, African oil palm, and the well-known species of sunflower, soybeans and Chinese sorghum, to name just a few.

But interesting as the exhibits are, what most attracts visitors is the beauty and tranquility of the park.

From the Arboretum's highest point you can see the Capitol building and the Washington Monument. But visitors can't help but feel they are in an oasis far away from the city and the world of politics.