Let's face it, holidays are expensive. You need to organise flights, accommodation, a rental car in Adelaide and so much more.

However, if you don't want to completely empty your bank account during your next trip, there is a way – try some free activities!

You can have a fantastic day out with your family or that special someone in Adelaide without having to part with a single coin. The following are the top four free activities we've come across in Adelaide.

1) Adelaide Botanic Garden

Here, you'll find world-class architecture situated amongst picturesque flora and fauna. You should put the International Rose Garden at the top of your to-do list, closely followed by the Bicentennial Conservatory.

The official website states that this building is "the largest single span glasshouse in the Southern Hemisphere," so don't forget to bring your camera. There is also an Australian Native Garden, which will give you the chance to view some plant life unique to our country.

Adelaide Botanic Garden is actually one of three parks, collectively known as the Botanic Gardens of Adelaide. If you have time and plenty of sun, make sure you visit Mount Lofty Botanic Garden and Wittunga Botanic Garden as well!

2) Migration Museum

If you fancy getting a little culture, head along to the Migration Museum and learn about the early days of South Australia. Located at 82 Kintore Avenue, it's right in the heart of the city – so it'll be easy to drive to in your rental car from Adelaide.

While you're here, you should definitely visit the 'Immigration in the Twentieth Century' exhibition. This contains artefacts and stories from different stages in South Australia's history, and gives a detailed overview of the massive impact this period had on Adelaide.

3) Aldinga Beach

You can't really say you've been to Adelaide until you've visited one of its stunning beaches – and Aldinga Beach is definitely the most popular. It's a scenic 50-minute drive from the city and perfect for swimming and surfing – as well as sitting, if you don't want to get wet!

South Australia's official website reveals there are many shipwrecks and exotic sea creatures lurking beneath the waves, so you may want to give snorkelling a try here, too!

4) 14 Pieces

If you're looking for a unique photo opportunity, take your family to see this exquisite piece of art. It's located outside the South Australian Museum on North Terrace, and consists of 14 slabs of beautifully sculpted black granite. These are covered in shallow pools of water that capture the light in a magical way.

You can walk between them or simply admire them from afar – it's up to you. And, of course, it's completely free!