The frontier between the Republic of Ireland and Northern Ireland runs for 310 miles.
After the Good Friday Agreement in 1998 the armed checkpoints and road blocks were gradually rescinded. Unmanned and meandering this invisible line is now crossed by approximately 35,000 people unchecked every single day. Following the referendum vote to leave the European Union this border will become the only land border between the UK and Europe. The majority of people in Northern Ireland did not vote to leave the EU. How Northern Ireland will be affected by Brexit is a concern for the continuing peace process and the NI economy.
Commissioned by Getty Images and latterly by the BBC I travelled along these roads.