Praia das Maçãs (Apple beach) is one of the most popular beaches within striking distance of Lisbon. The name comes from the fact that once upon a time apples would fall off trees upstream of the (Ribeira de Colares) river that flows along the southern side of the beach. These would then wash up on the beach - hence the name.
One reason for the popularity of this beach is the tram line which connects Praia das Maçãs to Sintra during the Summer months.
Being on the Atlantic coast the waves can be powerful here. This, however, isn't a problem as there is also a huge outdoor swimming pool equipped with slides, diving boards and a kid's pool right on the beach.