Which desert in Poland is often called the Polish Sahara?

The desert in Poland often called the Polish Sahara is the Błędów Desert.

The Błędów Desert, or Pustynia Błędowska, lies in southern Poland between Błędów, Chechło, and Klucze. It is Central Europe’s largest accumulation of loose inland sand, occupying about 32 square kilometres. The Biała Przemsza River divides the sandy area into northern and southern sections.

Its sand was originally deposited by melting glaciers thousands of years ago, but the modern desert landscape was strongly shaped by people. From the Middle Ages onward, forests were cleared to supply nearby silver and lead mining and metalworking. Logging and groundwater changes exposed and dried the sandy ground, allowing dunes and other desert-like features to develop.

The nickname can be misleading: Błędów is not a hot, hyper-arid desert like the Sahara, and its average precipitation is too high for a strict climatic definition of desert. Forest has reclaimed much of the area, while conservation work has reopened some sands. The Tabernas Desert, Deliblato Sands, and Oleshky Sands are elsewhere in Europe, not Poland.