Apple CEO Tim Cook at Apple's office in Cork in November. Twitter/Tim Cook Apple has publicly stated that it wants to significantly expand its operations in Ireland.

The Cupertino, California-based company employs 5,500 people in Cork, where its European headquarters is based — and Apple CEO Tim Cook has plans to hire an additional 1,000 people in the region by mid-2017.

But relatively little is known about what Apple does in this small city on the southeast coast of Ireland, which has a population of 120,000.

The company's main campus is in a suburban area of Cork called Hollyhill, while it also has another discrete, yet large, offices in the heart of the city.

Business Insider visited these sites — as well as a site for a proposed €850 million (£669 million) Apple data centre on Ireland's west coast — to see what we could find out. Apple did not allow us to enter any of its buildings.