text: p>The <a href="https://www.panynj.gov/bridges-tunnels/en/holland-tunnel/history.html" rel="nofollow noopener" target="_blank" data-ylk="slk:seven-year project" class="link rapid-noclick-resp">seven-year project</a> to dig out the Holland Tunnel, connecting New Jersey to New York, opened in 1927. Not only was excavation under the Hudson River water a feat in itself in the 1920s, but the project's chief engineer, Ole Singstad, created the first mechanical ventilation system used in a tunnel, helping dissipate the potentially toxic buildup of gases from vehicles using the tunnel.</p