WASHINGTON — The nation’s capital is under construction.

Along the National Mall, bulldozers and scaffolding have become fixtures beside some of the most recognizable monuments, like the Lincoln Memorial, where construction crews have worked for two years making extensive repairs and improvements to the Reflecting Pool.

Farther down the Mall, the Washington Monument is also closed, possibly into 2014, as crews repair damage from an earthquake last year.

And the construction is only beginning. A plan has been approved for work on an amphitheater near the Washington Monument, and to remake a pond that will be frozen into a skating rink in the winter.

In a town where even a nip or a tuck can be subject to severe scrutiny — and some politics, naturally — the changes are no small matter. They have been many years, and dollars, in the making.