Due to the thirty-year internecine conflict in Northern Ireland, the UK-Ireland border has had a special status since that conflict was ended by the Belfast Agreement/Good Friday Agreement of 1998. As part of the Northern Ireland Peace Process, the border has been largely invisible, without any physical barrier or customs checks on its many crossing points; this arrangement was made possible by both countries' common membership of both the EU's Single Market and Customs Union, and of their Common Travel Area.