The shell is the focal point of this painting. Where the shell's opening is, the human dwellings and transportation are visible while the opposite side of the shell appears to be underwater. this creates the same impossible effect as many Escher works.
The ships, buildings and aircraft appear to both man made and natural simultaneously. The shell and the city extending from it symbolize stability and safety. The interior of the shell shows a green field with a blue sky in the distance, symbolizing hope. The left side of the painting, the sea creatures, symbolize the unknown and it's danger and allure.
Overall I find this painting to be very aesthetically appealing and intriguing. I also enjoy the merger of human and natural accomplishments.