The incredible rise and fall of Tesco

British grocery chain Tesco reported its full-year results Wednesday - and it's a total disaster zone.

The company announced losses of £6.4 billion for 2014-15, its worst set of results in 100 years of trading and the first posting since CEO Dave Lewis took the reigns last July.

Lewis has been struggling to reform the company after revealing last September that it overstated profits by £250 million ($327 million), which eventually culminated in the resignation of Tesco's chairman, Sir Richard Broadbent.

Meanwhile, the company has been dealing with a separate but equally massive problem: disastrous global sales results. There are signs of improvement, but the share price is still less than half their value back in 2010.

So what went wrong?