Conflict and violence, persecution and human rights violations are driving more and more men, women and children from their homes
More than 35,000 people were forced to flee their homes every day in 2018 - nearly one every two seconds - taking the world's displaced population to a record 71 million.
A total of 26 million people have fled across borders, 41 million are displaced within their home countries and 3.5 million have sought asylum - the highest numbers ever, according to UN refugee agency (UNHCR) figures.
While much of the focus has been on refugees - that's people forced to flee across borders because of conflict or persecution - the majority of those uprooted across the world actually end up staying in their own countries.
These people, who have left their homes but not their homeland, are referred to as "internally displaced people", or IDPs, rather than refugees.
IDPs often decide not to travel very far, either because they want to stay close to their homes and family, or because they don't have the funds to cross borders.
But many internally displaced people end up stuck in areas that are difficult for aid agencies to reach - such as conflict zones - and continue to rely on their own governments to keep them safe. Those governments are sometimes the reason people have fled, or - because of war - have become incapable of providing their own citizens with a safe place to stay.
For this reason, the UN describes IDPs as "among the most vulnerable in the world".
ncreasing numbers are also leaving home because of natural disasters, mainly "extreme weather events", according to the Internal Displacement Monitoring Centre (IDMC), which monitors the global IDP population only.
there were 17.2 million people who were forced to abandon their homes because of disasters, mainly "extreme weather events" such as storms and floods, the IDMC says.
The IDMC expects the number of people uprooted because of natural disasters to rise to 22 million this year, based on data for the first half of 2019.
Mass displacement by extreme weather events is "becoming the norm", its report says, and IDMC's director Alexandra Bilak has urged global leaders to invest more in ways of mitigating the effects of climate change.
Tropical cyclones and monsoon floods forced many in India and Bangladesh from their homes earlier this year, while Cyclone Idai wreaked havoc in southern Africa, killing more than 1,000 people and uprooting millions in Mozambique, Zimbabwe and Malawi.
Large numbers of those driven from their home countries end up in cramped, temporary tent cities that spring up in places of need.
The biggest in the world is in Cox's Bazar, Bangladesh, where half a million Rohingya now live, having fled violence in neighbouring Myanmar.
The second largest is Bidi Bidi in northern Uganda, home to a quarter of a million people. The camp has seen many arrivals of South Sudanese fleeing civil war just a few hours north.
Bidi Bidi, once a small village, has grown in size since 2016 and now covers 250 sq km (97 sq miles) - a third of the size of New York City.
But what makes Bidi Bidi different from most other refugee camps, is that its residents are free to move around and work and have access to education and healthcare.
The Ugandan government, recognised for its generous approach to refugees, also provides Bidi Bidi's residents with plots of land, so they can farm and construct shelters, enabling them to become economically self-sufficient.
The camp authorities are also aiming to build schools, health centres and other infrastructure out of more resilient materials, with the ultimate aim of creating a working city.