SAN FRANCISCO — San Francisco-bound commuter traffic got an unexpected show this morning at the Golden Gate Bridge by an environmental protest featuring eight climbers who scaled the cables 500 feet above the deck. They were arrested for trespassing after being talked into coming down.

In addition, several people were charged with interfering with an officer because the climbers refused orders to come down, California Highway Patrol spokesman Bill Wylie said.

In all, 12 protesters were arrested, though only eight made the actual climb at the north tower. The protest, by the activist Earth First! organization, began in before dawn. Observers said the climbers were equipped with high-tech climbing equipment.

The protesters had planned to unfurl a huge banner advertising their cause, but never got to do it.