Millions of immigrants came from other countries, mainly from Europe and settled in America's cities, mainly in the urban centers.
Millions and billions
Millions of Europeans have immigrated over history. Most likely hundreds of millions.
The potential social effects are enormous from increased global warming. Whole populations are going to be starving and developing countries' governments are not rich enough to feed them. Whole countries will be trying to move to better climatic areas. Millions of climate refugees will be hammering at the door of the cooler countries.
Irish immigrants have come from all parts of Ireland. For hundreds of years Irish people have left Ireland and gone to other countries around the world. There are now millions of people all around the world that are Irish or have Irish ancestry.
In English-speaking countries, the billion is commonly defined as 1000 millions. In many other countries, it means a million millions.
In order to avoid religious persecutions, millions of Jewish immigrants arrived along with the third wave of immigrants (between 1881 and 1920). More Jewish immigrants arrived later.
Considering what he did he was more than just a potential danger, he was a real danger to millions of people.
They came, in the main, from Europe.
As of year 2009, the three Arab-speaking countries are Egypt, (79 millions), Algeria (34 millions), and Morocco (32 millions).