A turbine stage, comprising: a plurality of turbine blades, wherein each turbine blade comprises a respective airfoil integrally joined to a respective platform, each airfoil having laterally opposite pressure and suction sides (20, 22) extending in chord between axially opposite leading and trailing edges (24, 26); the turbine stage further comprises a row of said airfoils spaced laterally apart to define respective flow passages therebetween for channelling gases, each flow passage having a width; each platform has a contoured flow surface including a purge valley extending tangentially against a purge cavity wall into a blend area of the platform and having maximum depth at an elevation equal or greater than a nominal axisymmetric platform surface (θ) of the platform, the purge valley extending axially from proximate the leading edge of a first airfoil toward the suction side of the first airfoil, and toward the leading edge of an adjacent airfoil to channel a purge flow; at least some of said platforms each further include: an elevated bulge extending along a portion of each said airfoil and coupled to that platform, the elevated bulge adjoining said pressure side aft of said leading edge of each respective airfoil with the respective platform; and a bowl extending along a portion of each said airfoil and coupled to that platform, the bowl having a maximum depth lower than the nominal axisymmetric platform surface (θ) of the corresponding platform, the bowl adjoining the corresponding purge valley, said elevated bulge and said suction side aft of said leading edge of each respective airfoil with that platform; the purge valley, the elevated bulge and the bowl of each of the at least some of said platforms form an arcuate channel extending axially along that platform between adjacent airfoils. a plurality of turbine blades, wherein each turbine blade comprises a respective airfoil integrally joined to a respective platform, each airfoil having laterally opposite pressure and suction sides (20, 22) extending in chord between axially opposite leading and trailing edges (24, 26); the turbine stage further comprises a row of said airfoils spaced laterally apart to define respective flow passages therebetween for channelling gases, each flow passage having a width; each platform has a contoured flow surface including a purge valley extending tangentially against a purge cavity wall into a blend area of the platform and having maximum depth at an elevation equal or greater than a nominal axisymmetric platform surface (θ) of the platform, the purge valley extending axially from proximate the leading edge of a first airfoil toward the suction side of the first airfoil, and toward the leading edge of an adjacent airfoil to channel a purge flow; at least some of said platforms each further include: an elevated bulge extending along a portion of each said airfoil and coupled to that platform, the elevated bulge adjoining said pressure side aft of said leading edge of each respective airfoil with the respective platform; and a bowl extending along a portion of each said airfoil and coupled to that platform, the bowl having a maximum depth lower than the nominal axisymmetric platform surface (θ) of the corresponding platform, the bowl adjoining the corresponding purge valley, said elevated bulge and said suction side aft of said leading edge of each respective airfoil with that platform; the purge valley, the elevated bulge and the bowl of each of the at least some of said platforms form an arcuate channel extending axially along that platform between adjacent airfoils. an elevated bulge extending along a portion of each said airfoil and coupled to that platform, the elevated bulge adjoining said pressure side aft of said leading edge of each respective airfoil with the respective platform; and a bowl extending along a portion of each said airfoil and coupled to that platform, the bowl having a maximum depth lower than the nominal axisymmetric platform surface (θ) of the corresponding platform, the bowl adjoining the corresponding purge valley, said elevated bulge and said suction side aft of said leading edge of each respective airfoil with that platform;