Construction is finally under way on the Martin Luther King Jr. National Memorial on the Mall after 13 years of planning, fundraising and legal wrangling.

Workers have been clearing the site on the Tidal Basin since Dec. 28. They will move some trees to another part of the Mall, including a few of Washington's famous cherry trees. By February, heavy construction will begin.

Monday will mark the first King holiday, though, when organizers can finally see their work progressing.

"Everyone in the office is taking a deep breath," executive architect Ed Jackson Jr., said in an interview Friday. "Although it's been a labor of love, it's been a long road — 13 years for me."

It was supposed to be completed by now. President Bill Clinton signed a law authorizing the memorial in 1996, and President George W. Bush appeared at a ceremonial groundbreaking with Oprah Winfrey and others in 2006.

Numerous design approvals and a disagreement with the National Park Service over how to secure the site against domestic terrorism delayed the project.

"We had no idea it would take this long," Mr. Jackson said.

Still, he said, the years of work will pay off as millions of visitors will eventually see King's words carved in stone.

"Although it has been a long road, I am extremely fortunate to have an opportunity to be a part of it," Mr. Jackson said. "Obviously, I feel blessed."

The private foundation working to build the memorial is still raising money to complete it. To date, $108 million of the $120 million needed has been raised, spokeswoman Rica Orszag said.

In recent months, the Boeing Co. has been running television ads promoting the project. The group also is accepting $5 donations through a text message campaign.

Major infrastructure work will begin in February. It will take seven months to drive 300 concrete piles into the ground to support the granite memorial plaza and towering statue of King, Mr. Jackson said.

After that, the memorial will begin to slowly take shape.

The 28-foot "Stone of Hope" and "Mountain of Despair" sculptures will arrive in more than 150 pieces by May from China, where they were created. Sculptor Lei Yixin is scheduled to assemble the pieces between August and October.

A construction fence has been built around the site, but some places will be left open for visitors to see the progress.

In the final phase of construction, King's famous quotations will be engraved in granite along the water where memorials also honor Presidents Thomas Jefferson and Franklin D. Roosevelt. More than 200 cherry trees with their pink and white blossoms will be planted around the memorial.

A dedication and opening is expected in the fall of 2011.