First, some history:
Angola is one of the "plantation-style" prisons built in the early 1900s. During the Civil War, many southern penitentiaries---built on the Auburn System and thus were functioning factories---were destroyed by Union troops. Like the rest of the country, the South suffered a severe depression in the post-war years (especially in 1873). This was not the time to embark on the type of state-building efforts, particularly in the eyes of southern voters who preferred small and very local governments to big or centralized governments. Beginning with Mississippi, several southern states found alternatives to prisons with convict leasing---leasing convicts out to entrepreneurs (in some cases, the entrepreneurs paid the state per convict and the state paid for the prisoners' maintenance, in some cases, the state paid the entrepreneur to just take over the work maintenance of the prisoners) to do the work that free (white) labor would not do. Indeed, this was a highly radicalized system: states altered their penal codes such that the crimes typically committed by black Americans carried sentences of 1-5 years and were thus eligible for leasing; crimes typically committed by whites were punished by fines or, for some serious crimes, by lengthy prison sentences that were ineligible for leasing. Consequently, most leasees were black and most convicted felons given fines or served prison sentences were white. As opposition emerged in the Progressive Era, the Southern States embarked on a mini prison-building boom in the form of the plantation-style prisons. States bought large tracts of land that were previously plantations. Many black Americans were imprisoned for small offenses and then forced to work on the land they had previous worked on as de jure slaves---now as de facto slaves. (Indeed, the 13th Amendment only prohibited slavery for those not convicted of a crime.) Angola was first in 1901, followed by Parchman Farm (Mississippi) in 1901 and Cummins Farm (Arkansas) in 1902. (This is my quick and dirty summary of Oshinsky and Lichtenstein's excellent books on Mississippi and Georgia, respectively. See also Mancini's overview of convict leasing.)
These plantation-style prisons effectively continued some of the worst practices of slavery---and in some cases even graver atrocities well into the 20th century (see Perkinson's book on Texas and Feeley and Rubin's book on prison conditions litigation).
This history is not over. Policymic has a great article, "A Modern Day Slave Plantation Exists, and It's Thriving in the Heart of America." Offering striking visual images, Al Jezeera has done an picture article on Angola's prison rodeo---bringing prison tourism to new heights. The Atlantic has this piece on religion/reform at Angola. The New Yorker has this one on the shadow of slavery.
Supplement these with Liam Kennedy's fantastic piece on lifers at Angola. Angola has a large population of lifers (people sentenced to life imprison) and many others who are sentenced to extremely long periods in prison. Kennedy's article examines how this unique context, combined with Angola's extremely racialized past (and present), changed over the course of the punitive turn, noting that this national shift occurred very differently locally at Angola.
Teaching Pro Tip: When giving a lecture on prisons in the south, show images from 1880s-1940s of Southern prisons, then show images of the 1970s but leave the date out. The 1970s are after some of the first major court victories ordering prisons to change their practices, but the prisons continue to look much like they did in the 1930s. The striped uniforms, a predominantly black population with white overseers, prisoners working in fields and sleeping in barracks.
Teaching Pro Tip 2: Begin class with a recording of Rock Island Line (recorded in the 1930s as part of the public works effort and maintained by the Library of Congress). This version was performed by prisoners at Cummins Farm. The song is the kind whose rhythm is intended to aid field work in large groups as was done at these plantation-style prisons and on slave plantations.