Depositing cash in a savings account often appears to be the safest option for your money. However, over time the impact of inflation (a measure of the increase in cost of goods and services over time) can mean that despite the interest earned on the cash you have deposited, its real value in terms of purchasing power can gradually decrease.
To illustrate this, the black line on the graph below shows the performance of £1,000 invested as cash savings between 1995 and 2016, taking inflation into account.
As you can see, its real value has been eroded by over a third. For comparison, the orange line shows the performance of global equities (i.e. shares in companies around the world, not just the UK), which tripled in value over the same period. While it should always be remembered that the return on any investment cannot be guaranteed, a properly diversified portfolio comprising equities, bonds and other assets is likely to give you the best chance of beating inflation and providing a strong return while managing risk.