The scene shown here is Alessandro Botticelli's illustration of Dante's Inferno, Canto XVIII. It is a colored drawing on parchment, 320 x 470 mm, dating from the 1480's and is part of the collection of the Staatliche Museen, Berlin.
The colorful figures you see are Vergil, in blue, the guide to the underworld, and Dante, in red. Here is a brief overview of the scene they are observing, from John D. Sinclair's commentary on the Inferno.
More of these amazingly detailed, accurate, and imaginatively rendered illustrations here.
In the first ditch the two trains of panders [pimps--GH] and seducers, circling opposite ways but alike in their betrayal of innocence to lust, are driven by the scourges of horned demons, horns being traditionally associated with adultery, and their sin keeping them in eternal unrest. . . .
The second is the ditch of the flatterers and nothing less than its vile circumstances [they are wallowing around in a pit of excrement--GH] could express the nausea, emphasized by the unusual brevity of his account of it, that is felt by one of Dante's temper for their sin.