Although the engineering contributions of Marc Brunel and his son Isambard Kingdom Brunel are largely taken for granted, here they’re given their due. With the help of a shield system they invented, these pioneers executed the first tunnel to be built under a navigable river, but London’s soft earth didn’t make it easy. It took from 1825 to 1843, and this redbrick building marked by a chimney was where steam engines pumped the seeping water out as diggers toiled. The tunnel, lined with arches and Doric capitals, was a commercial flop that deteriorated into a subterranean red-light district. But it later found new purpose as a part of the Overground Line and new respect through this museum, which often creates special events to bring guests into the tunnel.