As bears love salmon i burn the whole Amazonas Forrest so glaobal warming proceds faster. During 1 day the whole Antarctis is completely ice-free. This leads to a massive increasement of sea level by 10m. Now there are salmons everywhere also on the hill (which is under water for sure, poor @Treim and his 9m hill), so the bears leave to hunt. Now there is you @Treim and me @Maxxxel but as u love salmon too u follow ur bears. Now i am the king of the hill and dive to the hills ground and simply pull a plug out of it. The water flows in there till the whole world is a dessert. I climb to the top to see my new kingdom... (far far away i can see a massive salmon hill, on the top there stands a bear and it looks like he sets @Treim as a defender with a salmon-catapult, weird oO)
As defense i set... nothing but the size of my hill, because of the water flowed in the past my hill now is 8848 meters high, try to climb that!
I now own the hill.