Who is Alfonso Calderon? Florida Shooting Survivor Gives Passionate Speech in Tallahassee

Alfonso Calderon, a junior at Marjory Stoneman Douglas High School, speaks with Broward County Sheriff Officer Brad Griesinger as he guards the front gate of the school in Parkland, Florida, on February 18. Calderon has become a major voice in the Never Again movement after 17 people died in a shooting at the school last week. Joe Raedle/Getty Images

As a slew of school shooting survivors descended on Florida's state capital to engage legislators and urge gun control and reform, Alfonso Calderon had social media's attention.

The 16-year-old junior attends Marjory Stoneman Douglas High School in Parkland, where 17 people died in a February 14 massacre. He gave a roughly six-minute speech at the Wednesday rally in Tallahassee, condemning adults who aren't taking student activism seriously and promising action "as soon as possible."

Calderon had joined busloads of fellow students and parent chaperones who traveled about seven hours from Parkland to the capital the day before.

Alfonso Calderon, a Florida school shooting survivor: “Trust me, I understand. I was in a closet locked, for four hours...I understand what it’s like to text my parents, ‘goodbye, I might never ever get to see you again, I love you’” pic.twitter.com/UaooVSPNNA

— BuzzFeed News (@BuzzFeedNews) February 21, 2018

The junior recalled being locked in a closet for four hours on February 14, surrounded by peers who were "crying and weeping on me, begging for their lives." He added he knew what it was like "to text my parents goodbye."

"We will not be silenced," he told the crowd. "I am prepared to drop out of school, I am prepared to not worry about anything else besides this."

Twitter users were buzzing Wednesday about Calderon's speech, with one user saying his words were "shaking my world to its core."

Alfonso Calderon in #Tallahassee right now is shaking my world to its core. These kids are mad af, and they’re going to change the world and I am here 100% for it and supporting them all the way. #MarjoryStonemanDouglasHighSchool #marchforourlives #neveragain

— thanks obama (@_m_m_c_g_s) February 21, 2018

Alfonso Calderon is incredibly eloquent and worth listening to

— Evan Siegfried (@evansiegfried) February 21, 2018

Watching Alfonso Calderon on @CNN and he is the future! He is going to be a leader! This movement deserves to be taken seriously! His opinion is valid maybe more valid than a senator who has only talked but never seen it first hand.

— Edward Guillen (@G12Edward) February 21, 2018

Calderon is a co-founder of the Never Again movement, which is demanding changes such as stricter background checks for gun buyers and is spearheading the March for Our Lives protest, slated for March 24. Other major players include senior Emma González, junior Cameron Kasky and junior Lorenzo Prado, who also spoke in Tallahassee.

Protests have popped up in other parts of the country as well, including in Washington, D.C., where 50 to 75 students staged a "lie-in" on Monday to symbolize the "atrocities" caused by gun violence. The movement utilizes the #NeverAgain hashtag.

Calderon is expected to speak at a CNN nationally televised town hall Wednesday night along with other peers. Florida Representative Ted Deutch, Senator Bill Nelson and Senator Marco Rubio have accepted invitations to participate, while Florida Governor Rick Scott and President Donald Trump declined.

Student activism has attracted the president's attention, however. Trump held a "listening session" with Marjory Stoneman Douglas High School students late Wednesday afternoon, and on Tuesday he announced he'd signed an executive order directing the Justice Department to look into a ban on bump stocks.

"School safety is a top priority for my administration," Trump said.