The Leaning Tower of Pisa closed in 1990 for the first time in 800 years. Engineers warned it was close to collapse. Over 11 years, they drilled beneath the north side and extracted soil. The tower settled back by 44 centimeters. It reopened in December 2001. Experts say it is now safe for at least 300 more years.
The Leaning Tower of Pisa Was Secretly Straightened
Most tourists posing for the classic "holding up the tower" photo have no idea they are standing next to a building that was on the verge of collapse. By 1990, the Leaning Tower of Pisa had tilted so far that engineers gave it a grim verdict: intervene now or lose it forever.
The Day It Shut Down
On January 7, 1990, the Italian government did something unprecedented: it closed the Leaning Tower of Pisa to the public for the first time in its 817-year history. The tilt had reached 5.5 degrees - past the threshold engineers calculated would trigger collapse. With nearly a million visitors a year walking through its seven floors of marble, the risk was no longer theoretical.
The Secret Underneath
A committee of international engineers, architects, and restoration experts spent the early 1990s studying the problem before committing to a solution. The approach they settled on sounds almost absurd: carefully remove soil from beneath the high (north) side of the foundation. By creating a controlled void on the non-leaning side, the ground would compress unevenly and the tower would gently tilt back toward vertical.
Starting in 1999, engineers drilled dozens of angled boreholes beneath the north foundation and began slowly siphoning out the underlying clay - removing only a few hundred liters at a time over weeks and months. To stabilize the structure during the process, hundreds of tons of lead counterweights were placed at the base on the high side. Steel cables were wrapped around the lower stories to guard against any sudden shift.
The Result
Over roughly 30 months of active soil extraction, the tower moved back by 44 centimeters - restoring it to approximately the same angle it had in the early 1800s. The project cost an estimated $25 million. On December 15, 2001, after 11 years of closure, the Leaning Tower of Pisa reopened to the public. Most visitors could not see any visible difference.
Still Standing - for Centuries
The intervention did not stop there. After 2001, the tower continued to self-correct naturally - no further excavation required. By 2008, sensors confirmed all movement had ceased. The total correction reached 48 centimeters. Experts now say the tower is stable for at least 300 more years. The lean remains - at about 3.97 degrees, it is still magnificently tilted - but the race against gravity has been won, at least for now.
Frequently Asked Questions
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Verified Fact
Verified Jun 15, 2026
Source: CBS NewsShow verification details
Verified 2026-06-15. Sources: CBS News (primary/cited source), PBS NOVA, Practical Engineering, geological-digressions.com, EF Tours, Smithsonian. Gemini cross-model comparison run on source text vs all fact fields. Claims checked: - Closure Jan 7 1990, first in 817-year history: CONFIRMED (World Footprints, CBS News, multiple). - 5.5 degrees tilt at closure: CONFIRMED (Practical Engineering; geological-digressions cites 5.4 in 1993, consistent with 5.5 at closure). - Genuine collapse risk: CONFIRMED (safety factor 1.07 - soil could take only 7% more weight; engineer Burland said masonry could go bang and blow up). - North/high side underexcavation method: CONFIRMED (all engineering sources). - Lead counterweights (hundreds of tonnes) on north/high side: CONFIRMED (600 tonnes initially, increased to 900 tonnes in 1995). - 44 cm correction by 2001 reopening: CONFIRMED (CBS News, Practical Engineering, multiple). - 48 cm total correction by 2008 (self-correction continued): CONFIRMED (multiple sources). - Approximately 3.97 degrees post-correction: CONFIRMED (0.5 degree reduction from 5.5). - Early 1800s angle as restoration target: CONFIRMED (1838 Gherardesca catino excavation worsened the lean; target was pre-1838 position). - Reopened December 15 2001: CONFIRMED. - $25 million cost: CONFIRMED by CBS News (cited source); other sources say $27M or 53B lire - defensible as approximate. - 300+ years stability: CONFIRMED (NBC News, EF Tours, multiple). - Post-2001 self-correction, movement stopped 2008: CONFIRMED. Corrections made to article body only (text/social fields unaffected): 1. CORRECTED lede: hours away from becoming rubble -> on the verge of collapse (no source supports a specific hours-away timeframe; safety factor 1.07 = genuinely at risk, not hours from failure). 2. CORRECTED: Steel cables were anchored to the fifth story -> Steel cables were wrapped around the lower stories (PBS NOVA, Practical Engineering, Ingenia all confirm steel tendons wrapped around tower up to the second storey, not fifth; fifth story was invented precision). 3. CORRECTED: bolted to the base -> placed at the base (lead ingots were placed/stacked in a post-tensioned concrete ring at foundation level, not bolted to masonry). Engine=2: Appropriate (tower is the story but is a landmark/place, not a human face/name driving FB Suggested push; exceptional engineering rescue story = Engine-2). mainstream_novelty=2: CONFIRMED (11-year closure and soil-extraction rescue is genuinely underknown; people know the lean, not the collapse rescue).
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