The history of the world is a history of migration.

But has migration gone too far?

Over the past few decades, the reasons for migration have multiplied.

Wars, famines and climate change are pushing people from their homes.

There's now the highest number of displaced people worldwide.

Some 66 million people have been forced elsewhere in the world.

Of these, 23 million are refugees.

The war in Syria has affected millions of people.

Some 3.3 million Syrian refugees currently live in Turkey.

Others fled to Europe.

Combined with this, there's also economic migration, both legal and illegal.

Since the mid 2000s, as the European Union expanded, several million people have migrated from Eastern Europe to Britain and other EU countries.

Each year, thousands of migrants from Sub-Saharan Africa get on boats off the coast of Libya to try and find work in Europe.

This sense of unprecedented scale has caused a backlash.

Anti-immigrant sentiment is on the rise.

Donald Trump capitalized on this when he talked about building a wall between America and Mexico.

Open border, it's a sieve.

We have no idea who's coming in.

In Germany, the right wing Alternative für Deutschland has become the biggest opposition party in parliament.

This may lead some to obey the strict controls of migration needed.

There is a liberal case for open migration.

Migration often makes a country richer.

Migrants from the EU are more likely to be paying taxes than taking our benefits in Britain.

Governments have a moral case for helping the most vulnerable in society.

With rich world countries shrinking demographically, they will also reap the benefits down the line.

But there are things we can do to help.

Smarter social integration.

Efforts to make immigrants stakeholders in society, not just long-term visitors.

There is no quick and easy solution to migration, but without making a liberal case for it, this will divide societies for decades to come.