On July 13, Sanford Underground Research Facility hosted its 16th annual Neutrino Day.
SURF, built at Homestake Gold Mine in Lead, South Dakota, is the deepest science laboratory in the United States. Research located underground at SURF includes experiments designed to study dark matter and, of course, the particles of the day: neutrinos.
The free, citywide Neutrino Day science festival featured tours, science activities and exhibits for all ages, talks and performances, and live video chats with engineers underground.
![A child listens to a communication device](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_01_Neutrino_Day_2024.jpg?itok=9ngVKQKv)
A child listens to a communication device brought by Colorado State University's hands-on science program, "Little Shop of Physics."
![A person on stage in front of a crowd](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_02_Neutrino_Day_2024.jpg?itok=O77Bdl_s)
PhD student Linda Di Felice, one of three presenters who gave a lecture titled Dark Matter 101: The LUX-ZEPLIN crash course, spreads her arms in front of the crowd at the Homestake Opera House.
![Children enjoy science learning and play with the Little Shop of Physics](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_03_Neutrino_Day_2024.jpg?itok=G0Kr5cZs)
Children enjoy science learning and play with the "Little Shop of Physics."
![People enjoy SURF's ethnobotonical garden Čhaŋgléška Wakȟáŋ.](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_04_Neutrino_Day_2024.jpg?itok=UkfL4oWH)
Visitors enjoy SURF's ethnobotonical garden, Čhaŋgléška Wakȟáŋ, defined by the lab as their "effort to explore the connections between science, art, culture, and humanistic inquiry in the Black Hills."
![Liquid nitrogen icream being made by volunteers.](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_05_Neutrino_Day_2024.jpg?itok=vSAatT9Y)
The South Dakota Mines chapter of the Society of Physics Students come to Neutrino Day each year to make liquid nitrogen ice cream.
![The tent for Fermilab at Neutrino Day was a popular place for many. Participants are gathered around the fermilab tent.](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_06_Neutrino_Day_2024.jpg?itok=p1FSutwG)
Volunteers from Fermi National Accelerator Laboratory, which manages the Deep Underground Neutrino Experiment under construction at SURF, talked to visitors about neutrinos.
![A child looks though VR goggles while a volunteer explains what they are seeing.](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_07_Neutrino_Day_2024.jpg?itok=xa_Mjk59)
2024 Davis-Bahcall Scholar Mackenzie Hollenbeck describes a VR image of the Deep Underground Neutrino Experiment caverns to a young Neutrino Day attendee.
![Poeple inside the Sanford Lab Homestake Visitor Center looking at the model of the SURF underground.](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_08_Neutrino_Day_2024.jpg?itok=4wWvGBLE)
A trio of Neutrino Day attendees, two human and one canine, check out a model of SURF's underground inside the Sanford Lab Homestake Visitor Center.
![Two people in front of a camera for a live broadcast from Neutrino Day](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_09_Neutrino_Day_2024.jpg?itok=OA-eor2X)
Two volunteers broadcast live from Neutrino Day.
![The crowd gathered for the live feed from underground during Neutrino Day.](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_10_Neutrino_Day_2024.jpg?itok=DhSHHJpP)
A crowd watches a live feed from underground at the lab.
![Volunteers at Neutrino Day smile while looking down from a balcony](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_11_Neutrino_Day_2024.jpg?itok=Ya0AovJ2)
Neutrino Day volunteers wave from above the crowd.
![A view from above Lead during Neutrino Day](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_12_Neutrino_Day_2024.jpg?itok=DcD6_Ye3)
SURF's Visitor Center is located next to the Homestake Gold Mine Open-Cut.
![A view from above Lead of a balloon launch conducted by South Dakota Mines](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_13_Neutrino_Day_2024.jpg?itok=-LOZtCYI)
During the Neutrino Day festivities, the South Dakota School of Mines & Technology launched a weather balloon.
![Two people smiling while holding the Neutrino Day selfie frame.](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_14_Neutrino_Day_2024.jpg?itok=gqzM-fQG)
Two Neutrino Day SURF volunteers smile while holding the Neutrino Day selfie frame.
![A view from above Lead on Neutrino Day with a full Main Street.](/sites/default/files/styles/2015_inset_one/public/2024-07/Inline_15_Neutrino_Day_2024.jpg?itok=sizYsgGn)
Cars line Main Street in Lead on Neutrino Day.
Editor's note: A version of this photo essay was originally published by Sanford Underground Research Facility.