And, Mass immigration can help to cause an economic strain, as more people are placed into medical wards at hospitals, school classrooms and into public housing. Due to the higher demand for housing and the lack of supply of said housing, immigrants are often placed into poor quality housing facilities in dilapidated neighborhoods. The lack of employment opportunities in these neighborhoods means that many are forced to turn to social welfare programs to get by. Some may restore to using criminal means to earn a living, selling drugs and other substances. In a poor economic climate (which realistically, many European countries are facing) there is already a low availability of employment. Those who get jobs are often payed very little, which drives down wages throughout the country. This leads to resentment of the immigrants, who are seen to be taking the jobs that the natives once had. Others who do not get employment find their days to be meaningless and pointless, and the land of opportunity they thought awaited them in Denmark or Sweden turns out to be an illusion. This leads them to resent the society they live in. Some return home. Others turn to vandalizing and rioting to express their anger and frustration. Some become radicalized by Islamic extremists, who prey on the downtrodden and ignored, and promise them revenge against the state and a purpose in their lives through spreading Islam. Those without jobs do not get to meet other natives, and are not required to learn the language of the country they reside in. They end up living in enclaves, like in France and Sweden, mostly living seperate from the rest of the country, a sort of island colony all onto itself.