[Ans] On what holiday did the 2017 March for Science take place?

Step 1 : Introduction to the question "On what holiday did the 2017 March for Science take place"

In 1969 at a UNESCO Conference in San Francisco, peace activist John McConnell proposed a day to honor the Earth and the concept of peace, to first be celebrated on March 21, 1970, the first day of spring in the northern hemisphere. 

Step 2 : Answer to the question "On what holiday did the 2017 March for Science take place"

In 2017, the March for Science occurred on Earth day (April 22, 2017) and will be followed by the People's Climate Mobilization (April 29, 2017).

Step 3 : Other interesting facts related to the question "On what holiday did the 2017 March for Science take place"

The first Earth Day celebrations took place in two thousand colleges and universities

In the winter of 1969–1970, a group of students met at Columbia University to hear Denis Hayes talk about his plans for Earth Day.

In addition to shutting down Fifth Avenue, Mayor John Lindsay made Central Park available for Earth Day

According to Nelson, the moniker "Earth Day" was "an obvious and logical name" suggested by "a number of people" in the fall of 1969

April 22, 1970, was coincidentally the 100th anniversary of the birth of Vladimir Lenin