Umihotaru
Umihotaru is a glorified parking lot built at great cost in the middle of the ocean – Tokyo Bay to be exact. The artificial island is known as umihotaru and the highway project goes by the name of Tokyo Aqua-Line, combining central Tokyo with southern Chiba prefecture. Connecting Chiba prefecture with Umihotaru is a bridge of about 4.4km. The whole thing took 31 years to finish. Officially it is a rest area for drivers but in reality it is for most people the only reason to use the tunnel. The island has restaurants, cafes, parking and rest spaces, a viewing deck – that is quite popular with plane spotters (Narita Airport is very close). There is even a Starbucks cafe on the island. As far as I know, the only Starbucks cafe in the middle of the ocean.