Catatumbo, Colombia – The Catatumbo region, which stretches along the border with Venezuela in the department of Norte de Santander, is Colombia’s most volatile frontier.Endowed with oil reserves and coca crops but impoverished and neglected, this border area has historically been a site of violent competition between armed groups fighting for territorial control.Recommended Stories list of 4 itemsend of listThe National Liberation Army (ELN), Colombia’s largest remaining guerrilla force, maintains a strong and organised presence, operating across the porous border with Venezuela.It is there that some of their fighters pick up an Al Jazeera reporting team and drive us to meet their commanders.Tensions remain high in this region. In January, thousands of people were displaced because of the fighting between the ELN and a dissident faction from the Revolutionary Armed Forces of Colombia (FARC) that continues to operate in some parts of the country in spite of peace agreements brokered in 2016.The fight is over control of the territory and access to the border with Venezuela, which is a crucial way to move drugs out of the country.Entering the area, it’s immediately apparent that the ELN is in total control here. There is no evidence of the country’s military. ELN flags decorate the sideroads, and the signs give a clear message of the way the group’s members see Colombia right now.“Total peace is a failure,” they say.There is also no mobile phone signal. People tell the Al Jazeera team that telephone companies do not want to pay a tax to the armed groups controlling the territory. Advertisement When President …