A turbine blade including a pressure sidewall (24) and a suction sidewall (26), and at least one partition rib (34) extends between the pressure and suction sidewalls (24, 26) to define a serpentine cooling path (35) having adjacent cooling channels (36a, 36b, 36c) extending in the spanwise direction (S) within the airfoil (12). A flow turning guide structure (50) extends around an end of the at least one partition rib (34) and includes a first element (52) extending from the pressure sidewall (24) to a lateral location in the cooling path between the pressure and suction sidewalls (24, 26), a second element (54) extending from the suction sidewall (26) to the lateral location in the cooling path between the pressure and suction sidewalls (24, 26). The first and second elements (52, 54) include respective distal edges (52d, 54d) that laterally overlap each other at the lateral location.