The famous "Welcome to Fabulous Las Vegas" sign will be powered by the sun.
The project to install solar power officially got underway yesterday.
Clark County officials approved the plan after the builders promised the so-called solar trees wouldn't show up in the background of tourists' snapshots.
The solar panels will be installed in three fake trees.
The project is being funded by a grant from the Consumer Electronics Association and donations from other organizations.
A plaque will explain how the solar powered welcome sign works.