A summer marred by fouled beaches, drought and sweltering heat came to its unofficial Labor Day finale with frustrated beachgoers demonstrating against pollution, and with a nip in the air over much of the nation.

Millions of Americans attended parades, foods fests and political rallies Monday. And though labor seems to have little to do with Labor Day 106 years after the holiday's inauguration, some people were even on the job.In Southern California, a third day of sizzling heat of more than 100 degrees drove an estimated 1 million people to beaches.

"It's pretty much a towel-to-towel beach gridlock out there by the water," said Malibu lifeguard Bill Barker, estimating that more than 200,000 sunbathers hit the beach.

But east of the upper Mississippi Valley, afternoon temperatures remained below 70 degrees.

The city-owned Wave Pool in Nashville, Tenn., drew only about 30 people as the temperature rose to the high 60s. The normal Labor Day crowd is 1,000.

As night fell, frost advisories were issued in Minnesota and Wisconsin.

A human chain of about 1,000 people stretched across two Long Island, N.Y., beaches, singing "America the Beautiful" and calling for an end to ocean dumping. Medical waste and other debris has washed ashore this summer from the Great Lakes to the Gulf of Mexico, ruining vacations for hundreds of thousands of people.

Others spent Labor Day laboring. But they didn't seem to mind.