Bentenjima Island
This was initially called Kodai Island.
But estuary construction in 1957 connected it to the mainland, so it is no longer technically an island.
Walkers on the 200-meter-long promenade that circles the island will see jagged rocks formed by many layers of hardened lava.
This happens when a submarine volcanic eruption pours out lava into the ocean.
As the lava cools rapidly it cracks and forms sharp edges.
Ubame oak trees that grow naturally on the rocks are another attraction of the island.
