As it has been estimated that the world’s population will exceed nine billion by 2050, global food demands will increase drastically in the future. However, because of climate change, we will need to feed our growing population with less arable land. To address this issue, vertical agriculture, an alternative to the traditional horizontal farming model, may be a potential solution that can give human beings a sustainable future. Vertical agriculture, also known as vertical farming, refers to the process of growing crops not only in rows, but also in stacked layers. Although it looks like a revolutionary farming method, it actually has a long history. The first known example of vertical farming is “The Hanging Gardens of Babylon” built in the sixth century B.C. At that time, the ancient Babylonians grew crops on water. It was considered as the world’s first concept of vertical farming. There are primarily three types of vertical farming—hydroponics, aquaponics and aeroponics. Hydroponics is the growing process where crops are grown with their roots submerged in a nutrient-rich water solution. This method is also getting more and more common in urban areas today. The second method, aquaponics, is a sustainable food production system where crops are grown in water that contains waste from fish, and they in turn clean the water for the fish. Finally, aeroponics refers to the process of growing crops with their roots suspended in the air. Farmers practicing aeroponics believe that crops will become healthier and grow faster when their roots have greater access to oxygen. Although vertical farming may help the world produce an abundance of fruit and vegetable, currently it still has several major limitations. The first issue is the cost involved in the implementation and maintenance of vertical farming systems. Because vertical farming technologies are still expensive, not every farmer can afford them. Another limitation is that vertical farming systems today can grow only a limited number of crops, making vertical farming still less economically viable than field farming. Thus, more research is needed to explore how to plant different crops vertically in large-scale systems.