Anxious travelers and their relatives have rejoiced, wept and breathed sighs of relief as the United States reopened to vaccinated visitors, ending 20 months of COVID-19 restrictions that separated families, hobbled tourism and strained diplomatic ties.
From Rainbow Bridge at the US-Canada border to Mexico's Tijuana crossing at San Ysidro, California, cars, motor homes and masked pedestrians on Monday clogged entry points from before dawn for eagerly anticipated reunions.
At airports and other US ports of entry, reunited relatives hugged as many met for the first time since the coronavirus swept the globe, leaving more than five million people dead and devastating economies.
Smiling passengers from the first European flight to land under the new rules at New York's John F Kennedy International Airport said it was great to be back as they entered the terminal to cheers and applause.
At airports in Europe, passengers queued excitedly to board planes bound for American cities, while those entering the country by land - some lugging suitcases or pushing bag-filled strollers under the watchful eyes of border patrol agents - faced hours-long wait times.
The ban, imposed by then-president Donald Trump in early 2020 and upheld by his successor Joe Biden, had become emblematic of the upheavals caused by the pandemic.
Mr Trump initially closed US borders to China travelers in February, 2020.
A month later he extended the ban to large swathes of the world, including the European Union, Britain, India and Brazil, in an effort to slow the spread of the virus.
Overland visitors from Mexico and Canada were also banned.
'Today is the day'
At Frankfurt airport in Germany, Hans Wolf queued at the check-in counter, visibly moved, bound for Houston to visit his son whom he had not seen in two years.
"We booked the first flights in March and had since then rebooked I think 28 times, and spent so much money in between that this flight must really be profitable now," he said.
At London Heathrow Airport, two planes from rivals British Airways and Virgin Atlantic heading to New York took off at the same time from parallel runways to mark the occasion.
To cope with surging demand, airlines have increased the number of transatlantic flights and plan to use larger planes.
Louise Erebara was at JFK in New York waiting for the arrival of her only sister and brother-in-law.
Hugs outside the US Customs and Border Protection gate at Boston's Logan International Airport Source: EPA
The women had not seen each other in 730 days, said Erebara, who admitted she would "cry hysterically" upon seeing her sister.
"It's been terrible not knowing when we were going to see them again due to COVID, not knowing if the borders would ever going to open," she told AFP. "Today is the day."
'Hug your grandchildren'
Along the US-Mexico border, many cities have faced economic struggles due to anti-COVID trade restrictions.
Reflecting widespread anticipation of the reopening, currency exchange centers in Mexico's Ciudad Juarez were hit by a shortage of dollars.
The Ciudad Juarez government implemented a special system to direct traffic, with portable toilets on the three border bridges and waiting times of up to four hours expected.
A woman reunites with her dog outside the US Customs and Border Protection gate at Boston's Logan International Airport Source: EPA
In Canada seniors will be able to resume their annual road trips to Florida to escape the bitter northern winters.
At the Thousand Islands Bridge into New York state, "there has been a wait since 11:30 last night," Canadian border services worker Scott Carl said as he directed motorists.
But the cost of PCR tests that Canada requires for cross-border travel - up to $250 USD - can be prohibitive.
Ann Patchett, an Ontario resident, told the Ottawa Citizen it will cost $500 for her and her husband to go south to visit family.
"Do you want to hug your children? Do you want to tuck your grandchildren into bed?" she asked. "It's very frustrating."
Some restrictions remain
Lifting the travel ban will affect more than 30 countries, but US entry will not be unregulated.
Authorities plan to closely monitor travelers' vaccination status and will still require them to present negative COVID tests.
Starting Monday, vaccines will be required for "non-essential" trips - including family visits or tourism - although unvaccinated travelers will still be allowed in for "essential" trips.
A second phase, beginning early January, will require all visitors be fully vaccinated to enter by land.
US health authorities have said all vaccines approved by the US Food and Drug Administration and the World Health Organization would be accepted for entry by air.
The WHO meanwhile expressed "grave concern" over the rising pace of infections in Europe, warning that the trajectory could mean "another half a million COVID-19 deaths" by February.