Stepping stone light by jihwan park from korea

Flowing water from a stream or a valley can be transformed into an energy source.

The city government, which consumes substantial amount of tax payers' money on maintaining
the night lights for the inner city streams should pay close attention to the
'stepping-stone light'. Stepping-stone light is lighting in form of stepping-stones
where continuous flowing water from the stream turns the hydraulic turbine which in turn
supplies electricity to the LED bulbs embedded within the stepping-stones.

It can be used as a precausionary safety device for perilous rivers and deep valleys.
It is economical for it does not demand maintenance after installment and can be used semipermanently.