shaft accident under the island. The tunnels, which pass directly beneath the island, are still used by the IRT Flushing Line (), and are now part of the New York City Subway system. Buildings from the tunnel stayed up until at least 1918. In 1964, the Norwegian fuel oil tanker Sigdal ran aground on the island, imperiling East River traffic. In 1968, the Hudson Institute published a proposal for connecting Roosevelt Island and U Thant Island by landfill to form a single larger island, as part of an economic redevelopment. 42nd Street would have extended across the island from Manhattan to Queens, connected by a Ponte Vecchio-like bridge covered in shops. "Belmont Center", modeled on Rockefeller Center, would have had towers of up to 80 stories. A Jet d'Eau–like fountain sponsored by George T. Delacorte Jr. stood nearby on Roosevelt Island from 1969 to 1987, and faced calls for its relocation to U Thant Island due to environmental hazards throughout its existence, at the time of its installation, in a 1972–74 lawsuit, and at the time it was finally demolished. In 1972, the island was declared "Soviet Jewry Freedom Island" and symbolically occupied for hours by activists led by Manhattan and Bronx Borough Presidents Percy Sutton and Robert Abrams to protest a United Nations speech by Leonid Brezhnev and the imposition of the diploma tax as a barrier to emigration from the Soviet Union. In 1977, the island was adopted by a group called the Peace Meditation at the United Nations, employees at the United Nations headquarters and followers of the guru Sri Chinmoy, who served as the interfaith chaplain there. They leased the island from New York State, greened its surface, and unofficially renamed it after the Burmese former United Nations Secretary General U Thant, a friend of Chinmoy. In 1982, Belmont Island was officially rededicated as U Thant Island. It is now the site of a metal "oneness arch", preserving personal items of the island's namesake. In 1999, The New York Times Magazine staged an international competition to design a time capsule to preserve artifacts for the next millennium. An entry by Caples Jefferson Architects proposed a granite obelisk on U Thant Island that would gradually disintegrate, leaving only the time capsule by the end of the 30th century. During the 2004 Republican National Convention, local artist and filmmaker Duke Riley, who has traveled to various abandoned islands