KatyK I never had a holiday as a child, either, only school day trips. However, from the age of 10, I spent my school holidays ( lived in NYC at the time) roaming the city on my own or with friends, packed lunches in a brown paper bag.
We spent entire days exploring a shop now sadly closed called FAO Schwarz, bigger than Hamley's and magical, investigating all the toys. We dressed, spoke and behaved well, so nobody every told us off.
As we got older, we visited museums. Didn't miss what we never had.
Such adventures not advisable now!