Uhhoarded Treasures

Those things seen on the surface
form the network of our world—
rain turned into rainbows
with their colors all unfurled.

This greatest spectacle
is spread out for all to see,
for the greatest treasures of the world,
blessedly, are free.

Even the biggest pessimist
among us must admit
that a bit of pleasure
may be derived from it.

Prompts today are surface, unusual, network, pessimistic, fee and rainbow.