Humpback whales draw crowds near Golden Gate Bridge

SAN FRANCISCO, CA – The Golden Gate Bridge in San Francisco is a big tourist attraction, now it's getting even more attraction because of some visitors underneath.

Humpback whales have been seen migrating through the waters.

Experts say the number of whales spotted has been "unprecedented."

They say this could be from a high concentration of anchovies and other schooling fish during incoming tides.

The whales generally feed further offshore and aren't used to navigating in shallower waters.

Some fear the whales could swamp boats when they breach, spook people jet skiing and sailing, or get hit by a ship.

The whales are migrating north after giving birth in the waters off Mexico and South America.