Inside Block history: Biggest winners from past seasons revealed

The Block is officially Australia's richest reality program, having distributed an astronomical cash total of $20,775,501 to contestants since premiering on Channel Nine in 2003.

The biggest winner in history has been Darren and Deanne with a total auction profit of $835,000. Watch video in the top player to find out which other couples have won big on The Block.

But while serious money has been made, auction day results are unpredictable. Not everyone has struck gold on the popular reality program. Watch the video below to find out which couples fell short when the hammer fell.

The Block Season 15 is set to premiere on Sunday, August 4, at 7:00pm on Nine.