Floodwaters rushed into New York's subway tunnels and left neighborhood streets across the Northeast looking like rivers. Homes washed off their foundations and onto a New Jersey state highway. Heavy winds sent power lines and trees crashing to the ground.
As they began surveying damage Tuesday, officials said it was impossible to measure the destruction Superstorm Sandy left behind.
"I don't think words like 'catastrophic' or 'historic' are too strong to explain the impact," New York Gov. Andrew Cuomo said. New Jersey Gov. Chris Christie described the devastation as "unthinkable."
More than 7.5 million customers shivered without electricity in 15 states and the District of Columbia in Sandy's chilly wake.
The storm also claimed at least 29 lives across the United States, bringing the total number of deaths to at least 97 after the storm wreaked havoc in the Caribbean.
Hundreds of people were stranded in one New Jersey town alone Tuesday. And Connecticut's governor offered ominous advice in a Twitter post: "If u find urself surrounded by water, call 4 help if u can, then get 2 highest level of home. Hang a white sheet out a street-side window."
Authorities scrambled in boats to rescue hundreds trapped in several towns after a berm broke in Moonachie, New Jersey. Some residents waited on rooftops for rescuers to arrive.
"Within 30 minutes, those towns were under 4 or 5 feet of water," said Jeanne Baratta, chief of staff for the Bergen County executive.
Meanwhile, the stench of smoke blew across flooded streets as fierce winds and rising waters shorted out power lines and sparked fires in places such as Lindenhurst, New York.
At least 80 homes burned to the ground in the Breezy Point neighborhood of Queens, fire officials said. The cause of the blaze was not immediately released. More than 200 firefighters battled the leaping flames.
Elsewhere in New York City, emergency backup power failed and 10 feet of water flooded the basement of NYU Langone Medical Center, prompting the evacuation of 260 patients. Nurses carried sick newborn babies down nine flights of stairs, manually pumping air into the lungs of those on respirators.
On Tuesday, nearly three-quarters of a million people in the city were without power, New York City Mayor Michael Bloomberg said, describing the damage Sandy caused as "enormous."
"The path of destruction that she left in her wake is going to be felt for quite some time," he told reporters.
When the storm hit, water poured into the ground zero construction site at a "massive rate," New York Gov. Andrew Cuomo said in a Twitter post.
Floodwaters rushed into the city's subway tunnels. Authorities said Tuesday they didn't know how long it would take to get the trains up and running again.
"The New York City subway system is 108 years old, but it has never faced a disaster as devastating as what we experienced last night," said Joseph Lhota, chairman of New York's Metropolitan Transportation Authority. "Hurricane Sandy wreaked havoc on our entire transportation system, in every borough and county of the region."
Atlantic City, New Jersey, became an extension of the Atlantic Ocean. Seaweed and ocean debris swirled in the knee-deep water covering downtown streets. Floodwaters ripped up part of the city's fabled boardwalk.
Like many New Jersey residents, Montgomery Dahm stared in awe at the water that deluged Atlantic City.
"I've been down here for about 16 years, and it's shocking what I'm looking at now. It's unbelievable," he said. "I mean, there's cars that are just completely underwater in some of the places I would never believe that there would be water."
The normally loquacious New Jersey governor struggled to find the words Tuesday morning to describe the images of devastation captured by helicopters surveying the damage along the Jersey Shore.
The roller coaster and log plume from a popular amusement park were in the ocean, Christie said, and homes were in the middle of Route 35.
"We're talking months to recover from this," he said.
A wide reach
The Northeast corridor of the United States bore the brunt of Sandy, but the storm affected a much broader area.
Fierce winds blew from northern Georgia into Canada and as far west as Lake Michigan on Tuesday. Meanwhile, heavy rains soaked New England and parts of the Midwest.
And in West Virginia, a blizzard spawned by Sandy knocked out power, toppled trees and covered streets with masses of wet snow.
"It's 3 feet of heavy snow. It's like concrete," said meteorologist Reed Timmer, who was riding out the storm in Elkins, West Virginia.
The full scale of Sandy's wrath has yet to be determined. But according to a government prediction, the storm's wind damage alone could result in more than $7 billion in economic loss.
One estimate Tuesday from Kinetic Analysis Corp., which conducts weather hazard assessments, said the storm's economic impact could be up to $25 billion.
After killing at least 67 people in the Caribbean, Sandy made landfall Monday night in southern New Jersey, sending waves of water into major cities along the East Coast.
Officials blame Sandy for at least 29 deaths in the United States, including 10 in New York City. Several victims, including an 8-year-old boy in Pennsylvania, died after being hit by a tree or tree limb. Another death was reported in Canada, where flying debris struck a woman.
As the devastation spread, President Barack Obama signed major disaster declarations for New Jersey and New York on Tuesday.
Hardik Rajput of Nassau County, New York, couldn't believe the sight of waves crashing over the height of cars.
"To be honest, I was just stunned," he said. "I've never seen that. Just to see it on the street level was astounding."
In New York, Manhattan's Battery Park recorded a nearly 14-foot tide, smashing a record set by 1960's Hurricane Donna by several feet.
As residents in New York and New Jersey surveyed the flooding left by Sandy, many discovered their high-rise apartment buildings became islands.
"I am looking outside of my sixth-floor apartment, and I see that a new lake has formed in the parking lot adjacent (to) my building," New Yorker William Yaeck said. "I would be concerned, but now my building has a view of the river."
-- CNN's Elizabeth Cohen, Josh Levs, David Ariosto, Joe Sterling, Katy Byron, Martin Savidge, Chris Youd, Soledad O'Brien, Elizabeth Cohen, Eden Pontz, Ed Payne, Ivan Cabrera, Chandler Friedman, Amanda Watts, Ali Velshi and Henry Hanks contributed to this report.