Anti-Keystone protesters are in Calgary as part of a North American movement called Draw the Line that aims to oppose the pipeline project.
Organizers say the goal is to draw a line to protect communities from climate change and to make a last stand against the Keystone XL pipeline being built.
The all-day vigil outside the TransCanada building is one of dozens of events taking place across Canada and the U.S. today.
Sixteen environmental groups are behind the efforts, including the Better Future Project, the Polaris Institute, the Rainforest Action Network and the Sierra Club.
"It's really kind of our last stand," said organizer Jane Kleeb.
Protesters in Nebraska have built an eco-friendly barn complete with solar panels and wind turbines that sits directly along the proposed route.
"It's essentially telling TransCanada and President Obama, 'If you were to approve a pipeline permit, TransCanada would have to tear down this barn since they can't have structures within the route.'"
In Calgary, the vigil is being organized by supporters of the Idle No More movement and Greenpeace.
It's taking a spiritual focus on the issue, with prayer, song and dance scheduled throughout the day.
In a press release, local organizers say the goal is to "preserve the environment, draw attention to the implications of the XL project and hold TransCanada, [the] Government of Canada, the Alberta government and the oil and gas industry accountable for the impact of responsible development."
Several big-name opponents of the Alberta oilsands have joined the Keystone debate recently.
Actor Robert Redford and musician Neil Young have both criticized the oil industry for its environmental record.
The province responded by saying it is doing all it can to ensure strong environmental standards as it continues to push for the pipeline to be approved.
"This is part of the ongoing challenge, to make sure that people understand the reality and don't get misled by these campaigns by others who don't seem to appear to have any attachment to science," said Ken Hughes, Alberta's energy minister.
"Let's not forget that there are already 80 pipelines across the Canada-U.S. border. There's a lot of oil going back and forth, a lot of natural gas and this is one more line that will help to continue to supply the North American continent."
Despite U.S. protests against the pipeline, Hughes insists 70 per cent of Americans support the Keystone XL project.