Big mistake
Is life all about the right answer?
If I told you that people would travel to look at a mistake, you would be wondering if they were insane. It is a tourist attraction and you the reader might know of it. It is the leaning tower of Pisa. To be fair to the builders, they did not know that the soil they build the tower on was not stable. That is not the mistake.
History
The builders first build it to second floor. They were then interrupted in a war. At this point, the tower was already tilting. This was literally a lucky break because it allowed the soil to settle. It was a century so the belief was that soil would have settled in that time. After the war, they continued to add additional floors. To compensate for the tilt, walls on one side of the tower was taller than walls on the other side. This would make the tower look perpendicular to the ground, but it would not affect the tower’s posture. That was the mistake. A historical kicking of the can down the road.
There was another war. Which led to another break. The last two floors took close to a century to be completed. At this point, the tower was good for another six hundred years. It was still tilting in an unsafe fashion, but it was a rather slow process. Galileo Galilei was supposed to have done his experiments on gravity in the tower. The Americans nearly destroyed the tower in WWII.
The Fix
A few decades ago, the Italian government discovered that the tower was about to collapse. More accurately, another ancient tower with a similar age as the tower in Pisa had collapse. That made the authorities concerned about the famous tower. The authorities reduced as much weight at the top as they could. They also anchored certain floors to the ground.
The Italians discovered a rather simple solution. By adding weights to the base of the tower, they could correct the leaning. The downside was that it was an eyesore.
When they tried a long-term fix, the tower nearly collapsed. The weights were rested on the walkway around the tower. The plan was to remove part of the walkway so they could do some work underneath. Unfortunately, the walkway turned out to support the foundation of the tower which started leaning quickly in the wrong direction. The authorities correct this problem by bring the weights back.
The Italians then discovered a more interesting long-term solution that corrected the tilt. They undermine the tower. By careful removal of soil from the base, they discovered that they were able to adjust the tilt. The fact that the tower is now open to the public meant that the undermining operation worked. Or at least it was adjusted back to its 1838 position. On one hand, nobody wants to see the straightened tower of Pisa. On the other hand, nobody knew that the 1372 version tilt was.
For greater details, you could listen to an engineer explain the civil engineering issues in detail.
Curse or Cure
The unstable soil beneath the tower was the reason for the leaning. However, it was also discovered that the unstable soil was likely to the reason that the tower could survive earthquake. The tower had survived four major earthquakes. As all things in life, sometimes you do not have to be good, you just have to be lucky.