Look to the skyline in the early hours of the evening tonight and you may or may not see an interesting message from Philadelphia's energy provider.

From 8 p.m. – 8:30 p.m. tonight the LED Crown Lights atop PECO's Center City Philadelphia headquarters will go dark in support of Earth Hour; an international effort to raise awareness about climate change.

According to Philly.com, the event has prompted a rolling blackout in each time zone from 8:30 – 9:30 p.m., attracting participants worldwide to shut down lights on buildings, bridges and in homes.

This year over 150 countries and territories including first-timers Palestine, Tunisia, Galapagos, The Kremlin, and Philadelphia's PECO headquarters will join San Francisco's Golden Gate Bridge, Chicago's Sears Tower, the Tokyo Tower and the Sydney Opera House in going dark for Earth Hour.

The Philadelphia Business Journal reports that beginning at 5 p.m. (before going dark) PECO will display this message:

"We're turning off our Crown Lights for Earth Hour on Saturday, March 23 8:30 – 9:30 p.m. Join us! Turn off your lights & save energy. Find more ways to save energy and money at peco.com/SmartIdeas."