In 1941, the Polish Government-in-exile in London authorized the creation of a top-secret special operations unit which existed for the sole purpose of parachuting into Nazi-occupied Poland to aid the fight for freedom. These highly-trained paratroopers were to assist with the planned uprising of the Polish underground resistance movement. They were called the Cichociemni -  which literally translates to "silent and unseen". Their emblem was an eagle holding a wreath encircling the symbol of the Polish resistance movement, a combination of the letters PW ("Polska Walcząca" - "Poland Fights"):

Many Cichociemni did parachute into Poland in the final years of the war - but it was not enough. You can read more here.

In 1995, the newly created special forces unit GROM (which means thunder in Polish) - adopted the insignia and traditions of their WWII predecessors:

I love seeing the symbols, old and new, side by side.