There are today more than 400 billion Lego blocks around the world, it is estimated, or around 50 per person.
But some of those blocks - or the sets they make up - are worth considerably more than others.
Rare Lego sets and minifigures can change hands for north of five figures, with two particularly sought-after models today valued at more than £10,000 each.
As well as being fun to play with, Lego can be a solid investment, with the price rise of limited edition sets often considerably outstripping inflation.
BrickEconomy provides a handy guide to the most valuable Lego sets today, whether they are still factory-sealed or very well-loved, and how their price could increase.
Below are the 14 most valuable Lego sets and minifigures right now, according to BrickEconomy.
They include a 1970s classic, Star Wars merchandise and several exclusive limited edition sets.
Could any of these be lurking in your loft?
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5. 4000000 Cars - £6,276.31
This was an exclusive set, only 33 of which were given away to attendees of the 2010 LEGO Inside Tour. A sealed Cars set is today worth an estimated £6,276.31, according to BrickEconomy.com, with a used set valued at between £5,110 to £5,798. | BrickEconomy/Lego Photo: BrickEconomy/Lego

6. 10123 Star Wars Cloud City - £6,474.07
This exclusive set with seven minifigures is based on the film Star Wars: Episode V – The Empire Strikes Back, and was released in 2003. A new and sealed set is worth an estimated £6,474.07, according to BrickEconomy.com, with a used set in good overall condition valued at around £2,818. | BrickEconomy/Lego Photo: BrickEconomy/Lego

7. 375-2 LEGO Castle - £6,700.95
This 767 piece set with 14 minifigures, also known as Yellow Castle, was released in 1978. It was the first ever Lego Castle and was only released in Europe, Australia and Canada. A sealed set is estimated by BrickEconomy.com to be worth £6,700.95 today, with a used set valued at between £202 and £308, depending on its condition. | BrickEconomy/Lego Photo: BrickEconomy/Lego

8. 4000031 LEGO Jurassic World Fallen Kingdom Exclusive T-Rex - £7,008.60
This 70-piece set was released in 2018, with only 500 being produced worldwide. A new and sealed set is worth an estimated £7,008.60, according to BrickEconomy.com, with a used set valued at between £5,586 and £6,337, depending on its condition. | BrickEconomy/Lego Photo: BrickEconomy/Lego