It is a special feeling to be so close to something that was created such a long time ago. If you ever get the chance to visit some rock carvings, I recommend you do it. If you are in Sweden here is a map of all antiquities.
The carvings have been filled with red to make them more visible. 
This carving shows some boats. The vertical lines represent humans on the ships. 
Frida Heskebeck 