This is the "before" image of the castle. 

This is the "after" image of the castle. First, I opened this image in Camera Raw and went through the Basic panel to make adjustments.  I increased the Exposure, Contrast, and Highlights and decreased the Shadows. I increased the Whites and Decreased the Blacks. I also increased the Clarity and Vibrance. Then I used the Spot Removal tool to remove some of the birds from the image because, to me, they just looked like black specks. I converted the image to black and white using Camera Raw and the Convert to Grayscale checkbox under HSL/Grayscale. Following the textbook, I went back to the Basics panel and made more adjustments. I ended up increasing and decreasing the Whites and Blacks (respectively) even more than earlier, and I also increased the Shadows. I increased the Clarity even more to give it more of a punch (as the textbook likes to say). Then I went under the Tone Curve panel and added a Medium Contrast to give the photo greater contrast.

This is the "before" image of the tunnel. 

This is the "after" image of the tunnel. I started in the Basic panel in Camera Raw and increased the temperature of this image just a little bit to warm it up. I also increased the Exposure. I converted the image to black and white by turning on Convert to Grayscale under the HSL/Grayscale panel. Then I went into the Split Toning panel in Camera Raw. At this point, I started a lot of experimenting. I went through warm colors and picked an orange hue for my Highlights, and I increased the Saturation to 40. I picked a blue hue for my Shadows and began playing with the Saturation. I ended up increasing the Saturation of my Shadows up to 40 as well, and decreased the Balance a little to favor the blue tint. I also went back to the Basic panel and increased my Clarity to show more of the details in all the stones of this image. Then I increased the Shadows to show more of the inside of the tunnel.