How did the people looking for a new house manage to get so large amounts of money to buy?

I am just very curious especially in the UK tv shows like Relocation Relocation, most of the people buying houses seem to have vast amounts of money at their disposal. Do they buy it in cash or do they have mortgages? I do not know of any mortgage lenders who would lend you �500,000 (unless maybe you really do have money to make a big deposit or you have a really high-paying job). Or maybe are they just really rich people? Thank you.