Environmental group Extinction Rebellion brought their message to one of North Wales' best known landmarks as other members continued to cause huge disruption in London.
Activists unfurled a banner from Caernarfon Castle on Thursday to draw attention to rising sea levels, following days of action which have brought parts of London to a standstill.
Bethan Russell Williams, who dropped the banner at the castle with John Williams, said: "It was about raising awareness locally about Extinction Rebellion and climate change.
"We couldn't all make it to London this week, but we can still do our bit locally.
"We are facing a climate and ecological emergency and we are asking the Government to declare an emergency.
"They must act now to reach net zero emissions by 2025. It was great to spread the word in Caernarfon among the locals and visitors to the town."
Extinction Rebellion aims to avert "climate breakdown", the loss of biodiversity and ecological collapse, and has been making headlines with its "Shut Down London" protests targeted at the city's transport infrastructure.
The group has also been active in North Wales for months, and blocked traffic on the Menai Bridge in November.
Campaigners stopped traffic on the bridge between Anglesey and Gwynedd while carrying placards warning of a "climate emergency".
On April 8, climber James McHaffie climbed a new route in the Dinorwig quarry near Llanberis and named it Extinction Rebellion, hanging one of the group's banners in the quarry to raise awareness of their campaign.
He said: "When it comes to climate change, we're in the last chance saloon and there's a very serious risk at stake.
"People need to know about this because at the end of the day it's about the planet we leave for our kids."
The group also had success with a motion backed by Gwynedd county council in March, which had been put forward by Cllr Catrin Wager, the councillor for the Menai ward in Bangor.
Her proposal, which came a week after the group presented a letter to the vice chair of the council, asked the authority to back the declaration of a "climate emergency", committing to taking decisive action to reduce carbon emissions and strive for a zero-carbon future.
It also included seeking "innovative means" to achieve zero carbon targets and to report back within six months on positive steps the authority had taken to reduce carbon emissions.
However, Extinction Rebellion criticised the council for not detailing how they plan to achieve a zero carbon future or whether the targets would be limited to the council's own emissions.
"We are keen to see how the council implement this policy if passed," they said.
