The Bible Belt is a term for the South-Eastern part of the United States of America, where Protestant evangelicalism is dominant in culture and government. The predominant religious type in this area is Baptist denomination of Christianity. The percentage of non-religious here are much lower than other areas of the United States and the world.
Origin of the Bible Belt
The Bible Belt includes the areas where slavery was very firmly established before the American Civil War. Slave owners in former slave states preferred to devastate their native land rather than give up owning fellow human beings like cats and dogs. Others at the time respected these slave owners and thought they were God-fearing. Maryland became a refuge for British Catholics though Catholics are not the majority there today. The part of the Bible Belt where Catholicism is strong is called the Rosary Belt.
Those who owned slaves or profited from other people’s suffering in different ways hired only religious leaders who taught what the oppressors liked. The Christian message became that slave owners could handle their property as they liked, that white men ruled while slaves, women, Native American and other non-whites should be obedient.
Christian teachings about social justice were ignored while instead the rich gave money to religious organisations and the rest were required to obey those over them without question. Believers were expected to believe the Bible as those preachers hired by oppressors interpreted it however unreasonable that may be. Morality involved sexual fidelity for women and obedience for women and children. Rich and powerful people did not even have to follow all of that. 
Political and Cultural Context
The term Bible Belt is used by it's critics to suggest that the religious influences the politics and education of the region. The Louisiana Creationism Act is one example of Christian bias in the Bible Belt.
An interesting look at the history of North America is American Nations, "A History of the Eleven Rival Regional Cultures of North America", by Colin Woodard. Most of them are the result of being settled by different groups of settlers, groups that took their customs and lifestyles and ideologies with them. Later settlers often moved to areas that they would be the most culturally compatible with, making the cultural differences persist. The differences continue to persist, as reflected in the divide between "red states" and "blue states".
In his chapter "Gods and Missions", he describes the rise of the Southern "Private Protestant" evangelical churches after the US Civil War. The churches were the main institution that the Northerners did not control in Reconstruction, and they helped develop the South's "Lost Cause" mythology. After the North more-or-less gave up, the Southerners had a counter-Reconstruction that they called "Redemption", and evangelicalism became dominant there. Part of its reaction against the North was its support of Biblical literalism and Biblical creationism, complete with passing laws against teaching evolution. This rather extreme Bible worship is what led to the term "Bible belt".
Bible Belt Statistics
- The divorce rate, the murder rate and the obesity rate are all higher in the Bible Belt than in the rest of the United States. Somehow the Bible Belt example isn't improving society.
- The Bible Belt has a higher murder rate than other regions of the United States 
- The Bible Belt's teen pregnancy rates are some of the highest in the country.
- There is more poverty in the Bible Belt than elsewhere. 
- Health overall is poor. 
- Sexually transmitted disease rates are also high. 
- hate and intolerance is well represented. 
- Those who can't or won't take the Christian values where they live secretly subscribe to porn.
The level of agreement in a state with the statement that “Even today miracles are performed by the power of God” predicted higher pornography consumption. States claiming to have old-fashioned values about family and marriage purchased substantially more adult-content subscriptions. 
From a logical standpoint, the Bible Belt's strict Christian morals (often forced) are causing controversy amongst the local population. This evidence is quite useful in a debate against a Christian when the overused "Christianity makes people moral" point is brought up. It also brings up the point that shoving Christianity down kid's throats does not work, and causes them to have contempt for Christianity. It's logical to assume that similar harm is probably happening in Christian fundamentalist Bible Belt type communities in other parts of America and the world. Statistics aren't so easy to get.
Any reasonable person who is not blinded by religious faith should see that something is fundamentally wrong with Bible Belt values.
Example to America and to the World
The Bible Belt of the United States shows to the United States, North America and to the whole world the harm done when twisted religious values become more important than ordinary human values.