The European parliament will vote on whether Bulgaria and Romania can join the region's free travel zone, known as the Schengen agreement, this week.<br /><br />The agreement allows people from member countries to travel without the need for any sort of visa.<br /><br />As part of the process to gain Schengen support, Bulgaria has been making efforts to show its borders are sealed.<br /><br />It has led to the creation of Bulgarian migrant detention centres, designed to look like a fortress.<br /><br />As unwelcoming as it looks, it's similar to detention fortresses in most of western Europe. <br /><br />People held in one fortress in Bulgaria were desperate to tell stories of their invisiblised lives.<br /><br />In the first of our special series on European border controls, Al Jazeera's Laurence Lee reports from a Bulgarian detention centre.
