@CNN: These crosses represent each victim killed in the Santa Fe High School shooting. Retired carpenter Greg Zanis has been placing such memorials at scenes of mass murders for 20 years. https://t.co/27mbqkSins https://t.co/zmM0lePdEz

@CNN: These crosses represent each victim killed in the Santa Fe High School shooting. Retired carpenter Greg Zanis has been placing such memorials at scenes of mass murders for 20 years. https://t.co/27mbqkSins https://t.co/zmM0lePdEz