A lot of big events in America's capital city -- from presidential inaugurations to historic political rallies -- take place on sweeping greensward in Washington, D.C., called the National Mall. And that historic lawn is going to get quite a bit of attention in the New Year.

You see, so many monuments and museums, not to mention millions of visitors, now pack the National Mall that it's looking more like New York City's Park Avenue than a park. So for the Mall's third century, agencies that have a hand in protecting it are swapping ideas about how to preserve the Mall's great vistas and enough open space for kite flying, holiday concerts, and the like.

In the 1790s, as part of his majestic plan for America's new capital city, eccentric French planner Pierre Charles L'Enfant envisioned a vast esplanade for grand homes, and, as he wrote, "all such sort of places as may be attractive to the learned and afford diversion to the idle."

But at first, sooty trainyards and a jungle of poorly-kept gardens bespoiled the Mall. A City Beautiful commission cleaned them out, but to take their place, along came a dozen or so massive Smithsonian Institution museums and an astonishing average of one new monument or memorial each year.

Congress now considers the Mall a completed work of civic art. But exceptions are made -- most recently, to squeeze in a memorial to General and President Dwight Eisenhower.

One idea is to expand the National Mall along the Potomac River to the Thomas Jefferson presidential memorial. It sits alone, along a basin ringed by Washington's famous cherry trees.

Something must be done for sure, and soon, say preservationists, else the National Mall will be as cluttered, and ordinary, as a shopping mall.