We are covering Slavery and Civil War in U.S.A. now so the following info and photographs should offer students some interesting insights...
Brazil was the last place in the America's to abolish slavery in 1888, so there are lots of photographs of the practice as you can see in the clip above. Indeed, according to NPR, Brazil has the "world's largest archive of photography of slavery."
Now, you can see many of those photographs at a new exhibition in Sao Paulo (the museum web site is in Portuguese). You can also read the excellent NPR story which includes some background about the history of Brazilian slavery.
Source: World History Educators Blog