The new lines of southern Lebanon

French UNIFIL peacekeepers patrol beyond the "yellow line" — the boundary of occupying Israeli forces — through the flattened towns of Houla, Kfar Kila, and Odaisseh. Israel has established a restricted buffer zone beyond that line after a U.S.-brokered ceasefire this year. Diego Ibarra Sánchez for NPR hide caption

The U.N. peacekeepers' armored vehicle moves slowly along the de facto border in southern Lebanon, not because of the terrain or the threat of shelling and drones, but because every mile means relearning a landscape profoundly transformed by war.

UNIFIL — the United Nations Interim Force in Lebanon — has been monitoring this area since 1978, when it was created to verify Israel's troop withdrawal after its first occupation of Lebanon.

The U.N. expanded UNIFIL's mandate 20 years ago to include monitoring adherence to a ceasefire in fighting between Israel and Lebanon's Iran-backed Hezbollah - the militant group created in 1982 to counter a second Israeli invasion.

Almost half a century later, the peacekeeping force's mandate will expire at the end of the year and due to U.S. and Israeli opposition, will not be renewed. There is still no durable ceasefire.

An agreement in June between Israel and Lebanon has brought only a fragile pause to a conflict that the Lebanese government says has killed more than 4,300 people, displaced more than 1.2 million and redrawn the geography of southern Lebanon since it began in March, when Hezbollah fired rockets at Israel. Israel says 39 soldiers and a military contractor, plus two civilians, have been killed in Hezbollah attacks since then. Seven U.N. peacekeepers have also been killed since the war began this year, according to UNIFIL.

The "blue line" — now marked by blue metal barriers — was the demarcation line drawn up by the U.N. for another Israeli withdrawal in 2000, after 18 years of occupation in southern Lebanon. Now marked by blue plastic barriers, it has served as a de facto border between two countries which has never formally agreed on boundaries.

Today, it remains on the map, but no longer fully describes the reality on the ground.