Media and telecommunications giant Comcast took a cue from Google Thursday as employees from several offices protested President Donald Trump's de-facto Muslim ban. And got a boost from Slack. 

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From Comcast headquarters in Philadelphia to offices in New York, Washington, D.C., and Silicon Valley, workers joined together to rally against Trump's executive order that temporarily bans immigrants from seven Muslim-majority nations and his call for a Mexican border wall. The rallies sparked the inspiring hashtag #TechHasNoWalls. 

A similar scene took place outside Google offices earlier this week, but Comcast's rallies had a unique starting point: Slack, the messaging and communications tool used by businesses.

Comcast employees organized Thursday's rally on a Slack channel that eventually pulled in an estimated 1,200 to 1,500 people in the past few days, according to reports. 

The hour-long rally at the Comcast Center, a skyscraper in downtown Philadelphia, drew at least a thousand people, with hundreds from Comcast, according to estimates. Other sites drew crowds of employees, as well. 

Comcast seems to be supporting the rally, according to an emailed statement. The company offered paid time off to workers participating. 

"Our primary focus is to make sure that all of our employees feel safe in their jobs, including while traveling. We have assured our employees that no one will be asked to travel to a place that would result in them feeling vulnerable in any way."

Huge crowds filled the streets outside Comcast's Philadelphia headquarters and peacefully chanted, marched and carried signs supporting immigrants, refugees and Muslims.

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