So-called third construction segment of the Birkenau camp, called Meksyk (Polish: Mexico) in the camp jargon. It was intended for 60,000 prisoners. Construction began in mid‑1943, but by January 1944 only 32 of the planned 188 barracks were complete, with a further 35 in the assembly or outfitting stages.

The decision to halt work was made at the turn of March/April 1944. When Jewish women from Hungary (Sonderaktion “Ungarn”) began being quartered there in mid‑May, there were no kitchens, washrooms, or latrines, and many of the barracks had no bunks in them. The prisoners received bedraggled summer dresses, and some of them went almost naked with only rags and scraps of blankets to cover themselves. Thus the name given to the segment may reflect the image of Mexico in the prewar press as a poor, restless country with a disorganized administration.

With the constant influx of transports from Hungary, Litzmannstadt, Płaszów, and evacuated labor camps on the one hand, and women being transferred to camps in the Reich or falling victim to selection on the other, the population fluctuated wildly while generally remaining above 10,000 women.

Meksyk was liquidated in early October 1944 and those prisoners who remained in the camp were sent to the women's segment (BIa).

(Mini dictionary of terms from the history of Auschwitz)