WASHINGTON - "To-night I have been wandering awhile in the Capitol, which is all lit up," wrote poet Walt Whitman in 1865.

"The illuminated rotunda looks fine. I like to stand aside and look a long, long while, up at the dome; it comforts me somehow."

It still comforts America.

But while you'd never know it to look at it, the Capitol Dome is slowly, gently crumbling.

As a result, Washington's most iconic symbol is undergoing a 21st-century-style face-lift. Soon, it'll look like a high-tech version of the planet Saturn, ringed by softly lighted scaffolding. Workers will be patching hundreds of cracks, scraping off the rust, and getting the lead out. The $59.5 million project aims to have the dome repaired and refreshed in time for the inauguration of the next president on Jan. 20, 2017.

In the meantime, no one is in danger of being struck by a falling ornamental iron flower from the dome. "The Capitol is in great structural condition," said Stephen Ayers, the architect of the Capitol.

The cracks are a growing problem. From a few hundred a decade ago, there are now an estimated 1,300.

Other problems appear on a walk up the 349 steep, inside-the-structure steps nearly to the top. There are the painted-over initials of Montgomery C. Meigs, the 19th-century supervising engineer. Something newer also appears: random brown lines and blotches, signs of current-day trouble.

The Capitol has been battling seepage for decades. Sometimes it's become a deluge - 23 years ago, birds clogged gutters during a storm, sending water pouring into the Rotunda.

That storm exposed other potential difficulties. "It became clear there were serious problems with the iron work," said Kevin Hildebrand, head of the architect office's architecture branch.

A big restoration project was needed. This fall, workers started taking precise measurements and surveys inside and outside the dome.

Visitors soon will find themselves amid a peculiar combination of construction site covers and some of the nation's most famous artwork. The Rotunda's paintings and statues will be covered for a few weeks early next year. A covered walkway will be set up to take people through the Rotunda.

When people look at the top, they'll see the Frieze of American History, which rings the ceiling ringed by what looks like a huge white doughnut.

Outside, the scaffolding will go up piece by piece, starting in the spring, eventually creating a virtual piece of modern art when it gets the LED light treatment at night.

On the scaffolding will be workers getting the 150-year-old dome up to modern structural standards. They'll remove the old lead paint. Cast-iron surfaces will get new coatings. Seams will be sealed. Broken windows will be replaced or repaired.

This is the latest update for a dome whose roots stretch to 1792, when William Thornton designed the first one. He envisioned a neoclassical building with a domed center, based on the ancient Roman Pantheon. In 1824, the first dome, wood covered by copper, was completed.

BY THE NUMBERS

288

Height, in feet, from the base of the Capitol's east side to the top of the statue

19.5

Height, in feet, of the dome-topping Statue of Freedom

108

Number of windows in the dome

8.9M

Weight, in pounds, of the dome's ironwork, built from 1855-66

SOURCE: Architect of the Capitol, EPAEndText