Sydney is the most populous city in all of Australia. It's also the most multicultural city in Australia, which makes it so fascinating to visit. The natural landscapes of the harbor, the ocean and nearby mountain ranges provide plenty of outdoor adventures. It's rich cultural landmarks and diverse population create an experience unlike anywhere else. It also means that there's so much to see and do in Sydney that tourists and visitors can easily get overwhelmed. Check out our list of the best Sydney apps for the iPhone and make the most of your trip down under.