Syrian conflict: Refugee life inside Lebanese camps
The population of Lebanon has swelled by more than 25% since the start of the Syrian conflict three years ago.
The UN Refugee Agency UNHCR will register the millionth Syrian refugee in the country on Thursday.
The vast majority of people fleeing the conflict end up in the tented refugee camps of the Bekaa valley.
But some are now seeking shelter in the Sabra and Shatila camps, on the outskirts of Beirut.
Sabra and Shatila are officially camps for Palestinian refugees who fled Israel after conflicts there and are run by the UN Agency for Palestinian Refugees UNRWA, rather than the UNHCR.
The UN has been informally supporting some of the Syrian refugees, but many do not want to register with the UN agencies for fear of endangering themselves or their families back in Syria and therefore do not receive any aid.
Estimates for the number of refugees now thought to be living in the Sabra and Shatila camps range from 10,000 to 22,000.
Living conditions in the cement and breeze block structures there are poor.
BBC News spoke to some of the Syrian refugees living in the camps.
Video journalist: Julia Macfarlane
03 Apr 2014