The protesters streamed into Hong Kong airport and quickly transformed the arrivals hall at one of the world's busiest transport hubs into a sea of black.
Instead of being met by smiling relatives and friends, passengers arriving at the airport were greeted by thousands of pro-democracy activists chanting "fight with Hong Kong, fight for freedom!"
Most were dressed in the movement's trademark black clothing, some sporting construction hard hats or gas masks.
And many added a new accessory on Monday: eyepatches or bandages to pay tribute to a woman who suffered a serious face injury at a protest on Sunday night.
The woman, who has not been identified, was reportedly hit by a beanbag round fired by police, and rumours circulated that she lost her vision.
Images of blood pouring from her face as she lay on a pavement quickly went viral and featured in posters calling for demonstrations under the banner: "an eye for an eye".
"HK police are killing us," read a sign held by one protester. "Hong Kong is no longer safe," said another.
And on walls, pillars and barriers in the airport, protesters sprayed painted red graffiti in English and Chinese reading "an eye for an eye".
"Hong Kong police are out of their minds, exceeding the level of force in their guidelines," said a 22-year-old protester who gave only his surname, Law.
"Hong Kong people must rise up and not be afraid."
Some protesters said the airport had been chosen as a venue for the demonstration because they believed police would not fire tear gas surrounded by international visitors.
"The police wouldn't act unreasonably because if people from other countries see how police can come in and hit people, that would be serious," said Kelvin Liu, a 19-year-old student at the protest.
- 'Sorry for the inconvenience' -
Protesters had already staged a three-day sit-in from Friday at the airport, handing out leaflets about their movement to arriving passengers.
But while several thousand people joined those rallies, the scene on Monday was vastly different, with people so tightly packed that it took 15 minutes to move through the crowd from the upper floor to the ground floor in the arrivals hall.
In the early afternoon, shops in the hall began to shut as the protest swelled, but well-organised volunteers moved through the crowd distributing water and food to the mostly young protesters.
Passengers looked confused as they exited wheeling their luggage, with some moving swiftly past the outstretched hands offering information about the pro-democracy movement.
But others stopped to look at the posters and artwork hung around the hall and talk with the protesters.
"I think they have every right to do what they are doing," said Rhiannon Coulton, 33, from Australia after she landed at the airport.
"I don't know if this will do any good for them, we will have to wait and see."
Coulton arrived in Hong Kong airport on one of the last planes to land on Monday after authorities announced all remaining flights in and out would be cancelled.
As protesters sang and chanted, an occasional muffled announcement could be heard from the loudspeakers above: "All flights have been cancelled, please leave as soon as possible."
Flight boards showed row after row of flights with their status reading "cancelled".
Underneath one protester had attached a sign: "Sorry for the inconvenience... But we're fighting for survival!"
Thousands of pro-democracy protesters rallied in Hong Kong airport, where flights were cancelled
Pro-democracy protesters in Hong Kong accuse police of using excessive force against demonstrations
The protests at Hong Kong airport come after the tenth consecutive weekend of demonstrations by a pro-democracy movement
The massive protest forced the cancellation of all flights in and out of Hong Kong airport