On January 8, 2024, clashes broke out at the World Headquarters of the Chabad-Lubavitch movement, a synagogue located at 770 Eastern Parkway in Crown Heights, Brooklyn, as construction workers, on behalf of the synagogue's leaders, attempted to fill in a tunnel that students had illegally dug beneath the building. The New York City Police Department was called to intervene and arrested twelve people.

The World Headquarters of the Chabad-Lubavitch movement are located at 770 Eastern Parkway in Crown Heights, Brooklyn and is often simply referred to as 770. The synagogue, located under 784 and 788 Eastern Parkway, has been subject to a dispute between the Agudas Chasidei Chabad (the umbrella organization for the worldwide Chabad-Lubavitch movement) and the Gabbaim, who are associated with Messianic Chasidim and control day-to-day operations of the main synagogue. Chabad messianists, in contrast to the beliefs of members of the mainstream Chabad organization, believe that the deceased Rabbi Menachem Mendel Schneerson is the Jewish Messiah and that he taught that 770 needed to be expanded. Though a court ruling in 2006 decided that full ownership of 770 belongs to Agudas Chasidei Chabad, ongoing legal disputes have prevented either party from altering the structure.

A grassroots campaign to enlarge the synagogue, called "Expand 770", was launched in 2022. The campaign aimed to rally support for the synagogue expansion. The campaign founder stated that there is a “need and duty to expand and broaden” the synagogue due to lack of space.

The New York City Fire Department reported that in mid-December 2023 they had been anonymously informed about a tunnel under the building and had responded to inspect it on December 20, but the tunnel was not detected. The existence of the tunnel was first publicly reported on by local media on December 22.

The tunnel was constructed by yeshiva students. The purpose of the tunnel was to begin illegally expanding 770, a process that has been delayed due to various legal disputes involving the building. Two yeshiva students involved with the creation of the tunnel spoke with The Forward, claiming that they were "taking initiative on a long-deferred synagogue expansion."

A New York City Department of Buildings investigation in January determined that the tunnel was "illegally excavated" and connected four neighboring buildings: 784 and 786 Eastern Parkway, 302 Kingston Avenue and the extension behind 1457 Union Street. The tunnel was approximately 60 ft (18 m) long, 8 ft (2.4 m) wide, and 5 ft (1.5 m) tall, with inadequate shoring. A full vacate order was issued for the abandoned men's mikvah at 302 Kingston Avenue due to foundation damage.

After the discovery of the tunnel, the gabbaim called in construction crews to fill the tunnel with concrete.

On the afternoon of January 8, 2024, a group of yeshiva students, reported to be Chabad messianics, attempted to protect the hidden passageways after a cement truck arrived to fill the tunnel. The men were seen tearing up wood paneling and throwing wooden pews while several of the men ran into the tunnel to stop it from being filled. The New York City Police Department responded after reports of a “disorderly group” outside the building.

Many refused to come out of the tunnel, and as a result, the New York City Police Department arrested nine people. Those arrested were between the ages of 19 and 22. Of those arrested, five men were later arraigned in front of a Brooklyn judge on charges including criminal mischief, reckless endangerment and obstructing governmental administration. The five men, who were described by their lawyer as being Israeli citizens studying to become rabbis, all pleaded not guilty and were released without bail until a future court date. Seven other individuals were given summonses on lesser charges. In April 2024, thirteen men were arraigned on charges relating to the incident.

Rabbi Motti Seligson, Chabad's media director, said in a statement that the incident was "deeply distressing to the Lubavitch movement, and the Jewish community worldwide." Seligson also characterized those that had created the tunnel as a "group of extremist students." Rabbi Yehuda Krinsky, chairman of the Chabad-Lubavitch movement, released a statement thanking the NYPD and stating that the actions of the students "will be investigated, and the sanctity of the synagogue will be restored." The building was temporarily closed, pending a structural safety review. The tunnel was infilled with concrete on January 10.

Residents of Crown Heights had varying responses to the incident with some concerned about those involved disrupting the sanctity of the site and highlighting the activities on a fringe group of individuals. Others connected with the reported expansion efforts of the group stating that the site visitors had outgrown its capacity and there needed to be an expansion on the property.

Footage of the January 8 incident and tunnel went viral, especially on Twitter. In other forums such as 4chan and QAnon Telegram pages, stills taken from videos of the synagogue's interior as well as the room leading to the tunnel, which showed a stained mattress and high chair, respectively, fueled antisemitic conspiracy theories. The claims fueling the antisemitic conspiracy theories were false.

• Hobby tunneling

• Expand 770 Campaign

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