Ometepe

The highlight of the trip was visiting Ometepe, a volcanic island in the middle of the gigantic Lake Nicaragua. We took a cheap little boat to the island for about $1.60, a ride of a little over an hour. As we approached the island with its two imposing, volcanoes Concepción and Maderas, with smoky gas pouring out of their tops, I began to wonder in the back of my mind what would happen if there were a serious eruption while I was visiting. As avalanches of lava raced down to the beaches, my only option would be to swim many many miles across the worlds' only shark-infested fresh water lake, Lake Nicaragua. If I survived the sharks, would I survive the exhausting swim? Too bad I didn't go to the gym more often when I had the chance. What about all the ash, the falling rocks, the blowing sand; what if the lake starts boiling? Well, at least then I wouldn't have to worry about the sharks.
Luckily, there haven't been any eruptions from Concepción since 1957 (or 1999 or 2005 depending on which line in Wikipedia you decide to believe), and Maderas has been silent since the 13th century and is considered dormant.
It turns out that the island is huge. It is 276 km squared and has a total population of 35,000 people with schools, health services, hotels, cell phone towers, and bananas. They export a ton of plantains. A truck from El Salvador boarded our ferry on the way back home, loaded to the brim with bananas.
As for those aggressive fresh water bull sharks, I didn't see any. According to the internet, studies from the University of Nebraska show that the sharks swim into the lake via the San Juan River from the Caribbean.
The river is a major waterway and the US originally wanted to use it as the basis for a Nicaraguan Canal, but they eventually built the Panama Canal instead. As of 2006, then-president of Nicaragua, Enrique Bolaños, was still trying to get a Nicaraguan canal built. He said it would be a huge economic boost for the country, but there are some problems, such as the huge construction cost and possible environmental damage.