The Nicaraguans call it "the Sweet Sea". In fact, it has everything it needs to be a sea except that the water is not salty: from one shore one cannot see the other, it has waves and archipelagos of islands, and the only fresh-water sharks in the world. Like any other sea, it has powerful storms and is dangerous to cross during such a storm.
The lake is connected with the Caribbean Sea by the San Juan River. Plans were made to take advantage of Lake Nicaragua to build an interoceanic canal, the Nicaragua Canal. Instead the Panama Canal was built, but interest in the idea of another canal in Nicaragua periodically revives.