The arrival five years ago of more than a million migrants in Europe caused widespread chaos and, despite a significant decline in arrivals, tensions and divisions have continued between EU countries over migration.
2015: Over a million migrants
Migrants increasingly start arriving in Europe from 2011, the year the conflict in Syria began. But it is in 2015 that the situation takes on dizzying proportions.
In April 2015 some 800 migrants from West Africa drown when a trawler sinks, in the worst disaster in the Mediterranean for decades. In late summer the number of arrivals rises and it tops a million over the year, with more than 850,000 going via Greece.
Fearing a humanitarian disaster, Germany's Chancellor Angela Merkel opens the country's doors, sparking criticism from other countries who fear the decision will create an influx. But soon Berlin reintroduces border controls, followed by other countries.
With difficulty, EU leaders agree in September on quotas for the distribution of asylum seekers from Italy and Greece, despite opposition from several Eastern European countries. But the temporary plan will prove laborious and conflictual in practice.
Fences start appearing along the migrant route, such as in Hungary and Slovenia.
2016: Turkey-EU deal
In March 2016 the borders shut down along the Balkans route from Macedonia to Austria, which migrants have been using since the summer as a means to reach northern Europe.
On 18 March, a hard-won deal between the EU and Turkey lifts some of the pressure: in exchange for financial assistance and political concessions, Ankara agrees for all migrants arriving in Greece to be systematically returned.
Over the year the number of migrants arriving in Europe falls drastically to less than 390,000. But tens of thousands find themselves stuck in Greece.
2017: Italy gateway
As the passage through Greece dries up, Libya becomes the key migrant route to the Mediterranean, and Italy becomes the main gateway to Europe.
Deals between Rome and Libyan authorities and militias in mid-2017 are a game-changer: support for the Libyan coastguard leads to a massive drop in arrivals, but also sparks criticism as migrants suffer detention and violence in Libya.
2018: Political crisis
Spain now becomes the main entry point to Europe.
In Italy in June, when an anti-migrant coalition including the far-right is sworn into government, one of its first actions is to refuse to allow the Aquarius rescue ship carrying 630 migrants to dock.
After a turbulent week at sea, the migrants are taken in by Spain, but the case leads to heightened tensions, particularly between Rome and Paris.
2018-2019: Mediterranean disputes
The decision in June 2018 by Italy's far-right interior minister Matteo Salvini to close access to Italian ports raises tensions further.
For more than a year migrant rescue ships are blocked in the Mediterranean for weeks until deals are reached between countries to take them in. In June 2019 a Sea-Watch rescue boat defies Salvini's orders and enters Italian waters despite the threat of a hefty fine.
Italy's government changes at the end of the summer 2019 and the country's ports reopen. In September Germany, France, Italy and Malta agree to automatically share the number of migrants who land in Italy or Malta, but the deal is suspended due to the coronavirus pandemic.
In 2019 fewer than 129,000 migrants arrive in Europe.
2020: Erdogan's 'blackmail'
In February 2020, Turkey opens its border with Greece, leading tens of thousands of people to cross from Turkey.
Fearing a repeat of 2015, the EU "strongly rejects" Turkey's "blackmail".
But the widespread closure of borders due to the virus crisis limits opportunities for migrants to cross into Europe, and the pandemic also leads to Italy and Malta closing their ports in April, and a scarcity of rescue boats.
At the same time, the pandemic accelerates the use of small boats for crossings in the central Mediterranean.
The International Organization for Migration warns of the risks that "invisible shipwrecks are occurring out of sight".
On a smaller scale - but in a sign that half a decade after the migrant crisis, Europe is far from having settled the issue - there is a sharp rise in migrant crossings of the Channel, causing tensions between Paris and London.