THE FLASH: “THE CURIOUS CASE OF BARTHOLOMEW ALLEN”

The CW, 8 p.m.

The Flash (Grant Gustin) gets blasted with a shockwave forcing his body to age prematurely.

EXPEDITION UNKNOWN

Discovery Channel, 8 p.m.; also streams on discovery+ Season Premiere! Adventurer Josh Gates is back for an 11th season of venturing into some of the world’s most mysterious places. The season premiere is the first part of a two-episode exploration that brings Gates and his crew into Poland to be the first people since World War II to enter a recently discovered hidden Nazi tunnel inside an extinct volcano. The team makes historic finds as they seek stolen art and uncover other dark secrets hidden away since the end of the war.