It’s a damp, freezing cold day in January, and I’m at the bottom of a massive hole in the ground. This is one of a pair of 41-meter-deep shafts in a part of east London called the Limmo peninsula, a spit of land on the banks of the River Thames. From a drone’s-eye view, it looks as though a giant hole punch has taken two neat circles out of the silty earth.
Back in late 2012, two enormous tunnel-boring machines were lowered into these shafts. Workers fired up the 1,000-metric-ton behemoths (named Elizabeth and Victoria), and their rotating cutting heads slowly gouged their way westwards. When they finally reached Central London in May 2015, it marked the completion of the tunneling work on Crossrail, a new underground railway system that spans London.
Crossrail will be fully operation by the end of 2019, with an expected 200 million passengers carried through its arteries every year. For now, it is Europe’s biggest construction project, with a budget of £14.8 billion (about US $21 billion).