This is the VOA Special English SCIENCE REPORT.
Engineers are celebrating the completion of repairs to the Leaning Tower of Pisa. Italian officials closed the Leaning Tower for safety reasons eleven years ago. Experts now say the repairs will make the building safe for at least a few more centuries.
The Leaning Tower is famous around the world. Many visitors to Italy travel to the city of Pisa to see the unusual-looking structure. The round tower is more than eight-hundred years old.
The Leaning Tower of Pisa is easy to recognize. The white stone building is sinking, or leaning, on one side. The tower is about fifty-five meters high. Its south side is much lower than its north side.
The Leaning Tower is leaning because it was built on soft sandy soil. The soil cannot support its weight. The tower weighs about fourteen-thousand-five-hundred metric tons. The ground under the tower first started to sink soon after workers began building the structure in the year Eleven-Seventy-Three.
In recent years, the Leaning Tower has continued to sink. Experts expressed concern that the tower might fall suddenly. In Nineteen-Eighty-Nine, a similar tower in the Italian city of Pavia fell. Four people were killed. The following year, Italian officials closed the Leaning Tower of Pisa. People were no longer permitted to walk up to the top.
An international team of building experts began a project to make sure the Leaning Tower does not fall down. The project cost about twenty-five-million dollars.
First, engineers placed eight-hundred-seventy metric tons of lead weights on the north side of the tower. This helped stop additional movement. Also, workers tied strong steel cables around the structure. These wires were connected to large weights in the area.
Next, engineers slowly removed tons of soil from under the tower. They used special drills to remove small amounts of soil over several months. Slowly the tower moved back to where it stood hundreds of years ago. It still leans, but not as much as before the repairs.
Last month, the area around the Leaning Tower opened to the public. However, visitors will have to wait until November before they are permitted to climb to the top. Italian officials say only about thirty visitors will be permitted to climb the tower at one time.
This VOA Special English SCIENCE REPORT was written by George Grow.