Medal 1843, Opening of the Thames Tunnel - Sir Isambart Marc Brunel - BY James Taylor. White Metal. 43.8mm. Scare. The opening of the Thames Tunnel marked a monumental achievement in civil engineering and remains a significant historical event. Officially opened to the public on March 25, 1843, the tunnel was the world's first underwater tunnel, running beneath the River Thames in London. The mastermind behind this ambitious project was the renowned engineer Marc Isambard Brunel, with significant contributions from his son, Isambard Kingdom Brunel, who would later become one of Britain's greatest engineers. Construction began in 1825, employing a revolutionary tunneling shield designed by Marc Brunel. This innovative technology allowed workers to safely excavate the soft riverbed soil, which had previously posed insurmountable challenges. Despite numerous difficulties, including flooding, financial problems, and health hazards faced by the workers, the tunnel was completed after 18 years of labor. Upon its opening, the Thames Tunnel was celebrated as an engineering marvel and attracted significant public interest. Initially, it served as a pedestrian thoroughfare, with thousands of visitors paying a penny to walk through the tunnel and marvel at its construction. It soon became a popular site for tourists and was even used for fairs and exhibitions. In the late 19th century, the tunnel was converted for railway use, becoming part of the London Underground system. Today, it is part of the East London Line, continuing to serve as a vital transportation link and a testament to the ingenuity and perseverance of its creators. The Thames Tunnel remains a symbol of industrial progress and a landmark in the history of engineering.