This image was produced by creating a Curves adjustment layer, over the original layer, and altering it thus...
However this adjustment did not do much to remove the blue tint to the hills.
Note that the bottom of the curve has been brought in, so that the full tonal range is used. Then I have slightly adjusted the curve to try and increase the contrast (steeper curve) in the main hills and distance.
One of the things this does is also change the colours as the RGB channels mix up tone and colour. A lot of the time this actually helps by increasing the colours automatically for you.
If you go back and flick between the AutoContrast image and this Master channel image, you will notice the difference in the tones of the background - this is because of this bent curve compared to the straight line that the AutoContrast would have produced.
I always use an adjustment layer, rather than Image>Adjustment>Curves... so than one can go back and change it!
To create an adjustment layer via the menu, use Layer>New Adjustment Layer>Curves... and then you need the Layers palette visible by Windows>Layers in order to re-select it.