History's great mistakes

( A gallery of some of the world's worst blunders, oversights and no-brainers according to today's Telegraph Expat's newsletter)

-> The Coca Cola Company made a series of errors in the early 20th century, when its biggest rival, Pepsi, struggled to avoid bankruptcy. On at least three occasions, Coca Cola was offered the chance to buy the company – but never did. The companies have vied for supremacy in the cola market ever since.

-> It took 177 years to build, but the Pisa’s famous tower began to lean less than a decade after construction began. The enormous project was planned on unstable soil, and had a shallow three metre foundation which couldn’t support the structure’s weight. After extensive renovations, the tower has now stopped moving for the first time in its history.

-> "In the Dome we have a creation that, I believe, will truly be a beacon to the world," declared Tony Blair in 1998. Poor old Tony. The dome ended up costing nearly £800 million, only attracted half the number of people it aimed to, and sat empty for years before - finally - being converted into the 02.

-> Christopher Columbus landed in America in 1492. However, the fortuitous discovery which allowed Spain to colonise America was little more than a mistake. Columbus had been hoping to reach China and India, and believed that they could be reached by sailing west across the Atlantic. This is why, of course, he called the indigenous population Indians.

-> Captain George Custer had always wanted fame, but the disastrous Battle of Little Big Horn in 1876 ensured him a reputation only for arrogance and miscalculation. He had estimated only a small number of Native Americans would fight his troops, but his entire company was killed by an army of thousands.

-> Remember the moment in ET when Elliot lures the little extra-terrestrial into his house with a sweet called Reese’s Pieces? Well, you may only know of that particular treat because of of it. Spielberg had tried to get Mars to let M&Ms be featured in the film, but was turned down. After the film was released, sales of Reese's Pieces rocketed by more than 65 per cent.

-> RMS Titanic, the largest passenger steamship in the world, was popularly believed to be unsinkable. The huge loss of life that occurred when it crashed into an iceberg in 1912 was due partly to an inadequate supply of lifeboats, and partly to design flaws – including an unreliable system of watertight compartments, and poor quality rivets in the ship's hull. After the ship sank, a number of safety improvements were introduced to boat design.

-> In 1961, Decca Records auditioned a small Liverpool band in their London studios. Eventually, however, they decided that the group wasn’t sellable. Not long after, they signed with EMI. The group’s name? The Beatles.

-> In 1907, Theodore Roosevelt decided to send the US navy on a round-the-world cruise, believing the event would prove America's power and strength. But by using his position as Commander-in-Chief to avoid negotations with Congress, Roosevelt's actions set a dangerous precedent for presidents to exert total power.

-> After a bad dream the night before his murder, Julius Caesar's wife warned her husband not to go to the Senate. The moral of this mistake is, perhaps, to always listen to your wife.

-> His name is now synonymous with genius, but Albert Einstein was so unsuccessful at school that his teachers believed he had had learning difficulties.

-> "This 'telephone' has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us.” So said Western Union, the company with a monopoly on the telegraph system, when offered the patent for Alexander Graham Bell's new invention in 1876. Two years later, they offered $25 million for it, but were turned down.

-> The Battle of Agincourt, painted by Sir George Gilbert, should have been an easy win for the French troops. Yet though far bigger than the English army, their underestimation of English long-bow tactics, combined with the fact they had packed themselves so tightly they could hardly use their weapons, resulted in defeat.