Despite sweltering heat Sunday, thousands hit the streets in Philadelphia ahead of the Democratic National Convention as part of the March for a Clean Energy Revolution.

Organizers and participants said they don’t support any particular candidate, but want Democrats to see the public’s support of solar, wind, water and other natural forms of energy.

“If you care about clean energy, you’ve got to educate yourself, you’ve got to know the issues, you have to know where the candidates are and the things you care about and you’ve got to vote,” said Tom Gilbert, 46, from Pennsylvania, as hundreds of marchers gathered around City Hall on Sunday. “No vote, no voice. That’s not a partisan thing at all.”

Protesters included people from California and Nevada, religious organizations, youth and Ramapough Lenape Indians. They were all in attendance along with people from across the East Coast.

The strong turnout is the first sign that the intense heat wave sparked by a “heat dome,” to be followed by severe thunderstorms starting Tuesday, won’t deter the thousands of protesters who have pledged to march around the city for various causes to get the attention of top Democrats and presumptive presidential nominee Hillary Clinton.

See below for Metro’s calendar of scheduled DNC protests.