A one-inch wide, four-foot long crack was spotted Wednesday in the Washington Monument's pyramidion, near the very top of the 555-foot obelisk. (U.S. Park Police Aviation)

Five U.S. Park Service Police photos released late Wednesday show why the monument remains closed to the public — a block appears dislodged in the top of the monument and debris is scattered on the stairs and observation deck where millions of visitors have taken a look at the Capitol, Pentagon, White House and Lincoln Memorial.

From inside the pyramidion of the Washington Monument, a block appears to be dislodged.

Fallen debris on the floor of the observation deck, where millions of tourists have trod.

Debris on stairs coming down from the Washington Monument's observation deck.

Steve Lorenzetti, USPS deputy superintendent of planning, and Robert A. Vogel, USPS superintendent of the National Mall and Memorial Parks, confer with civil engineer Ned Wallace inside the Washington Monument.

The monument was initially closed right after the earthquake struck at 1:51 p.m. Tuesday. The National Park Service is making no predictions when it will reopen, because evaluations are still underway.

“We have to let the structural engineers do their job. That may take a week to 10 days,” said NPS spokesman Bill Line. “It may take a week or two after that point for them to pull things together and write a report that documents the amount of damage done, and to make recommendations. The Park Service will have to evaluate that.”

Aware that visitors to the nation’s capital love to ride the elevator to the top of the monument and gaze at the federal city and horizons, and that hundreds of thousands of visitors are due this weekend for the dedication of the new Martin Luther King Jr. Memorial, Line said the service cannot take any chances with safety.

“It’s impossible to say how long repairs will take to complete. Then we’ll have to have repairs inspected and certified,” Line said. “I know we live in this instanteous world where everything is expected to happen instantly, but we have to be correct.”

Visitors who feel height-deprived may want to consider the 270-foot elevation of the Old Post Office Pavilion tower, which was closed briefly after the earthquake Tuesday and is now reopened.