wow, I had no idea!
i've never paid much attention to ours, so they are probably non descript looking..
Today, nearly 95% of the 1,780 municipalities in Japan sport their very own customized manhole covers, with imagery that evokes each region’s cultural identity, from flora and fauna to landmarks and local festivals.
As a testament to the Japanese aesthetic sensibility in all aspects of life, these pieces of urban art are colorful, intricately designed, and unique to their locale - from Kanto to Chubu to Disneyland Japan.
( 2 or 3 are the same as the OP ) 