makes a lasting impression; has an obvious effect
Example: The volcanoes in the region have made their mark on the landscape.
To hollow out something is to remove the middle part of it to make a space.
Example: She hollowed out the pumpkin to make a lantern.
Your mind's eye is your imagination.
Example: I can still picture her in my mind's eye.
Notice that the possessive apostrophe comes after the 's' when more than one is involved. Follow the link for more.