The verb of the sentence is "gazed", the subject of the sentence is the mountain.
The flow of thought in how the writer conveyed the story or information is not fluid. It was not arrange making it look more of a mixture of thoughts not sure whether the subject is about the memory or the beach. Another is that the information was being redundant say for example the first and last sentence where the writer mentioned happiness first and then glad again on the latter part.
Rewriting the paragraph capturing every information the writer had wished to convey in simple terms would go something like this.
I remember my happiest childhood memory was at the beach where i learned how to swim. Local beaches does not only offer a nice place to swim but many other activities. Scuba-diving, surfing, beach volleyball and the like. As such i wish for people to experience the same thrill and spend more time there than at home.