Six years on, Kevin returns to Scotland to see Colin and Marta's incredible metal home, inspired by aircraft hangars, now that the construction is finally finished

Edward and Hazel plan a shining white art deco lighthouse on a rugged beautiful clifftop. But almost immediately their wildly optimistic plan runs into trouble.

In one of Grand Designs most disaster-laden projects, Edward and Hazel Short looked to build a vast lighthouse-inspired home in Croyde, on a crumbling clifftop the North Devon coastline. The grand plans for the build saw loans of £3 million taken out to fund the project, but with setbacks and delays, the money was soon gone, leaving the building half-finished. Edward estimated that it would take another £2 million to complete the build.

After recovering from leukemia, Toby is driven to build a complex home around an old oak tree. But can he balance high architecture and health with a comfy family place?

Richard and Felicia almost single-handedly turn an underground water reservoir in the Humber Estuary into a family home. It's an epic task. And then a life threatening illness strikes.

Design engineer Mark Butler is paralysed from the waist down and needs a cutting-edge, wheelchair-friendly family home. Making it for £600k proves a huge emotional strain.

Kevin McCloud meets entrepreneur Paul Wilkinson and his wife Amy, who are building a giant new home on a 16-acre plot in Lincolnshire. The superstructure will be comprised of five circular buildings made up of interlocking timber cylinders, linked by raised wooden walkways that hang over a fishing lake. The complicated build proves difficult for Paul's local team, and their ambitious schedule of completing the project in a year soon looks out of reach.

Kevin McCloud meets Andy Stakes and Jeanette Hardy, who are building a new house on top of a sheer cliff on the west coast of Scotland. The pair want to spend £250,000 on a two-bedroom, glass-fronted and earth-sheltered home for themselves and their two beloved Newfoundland dogs. However, construction on such an exposed site is fraught with danger and the pair face no end of problems throughout the build, and a last minute design change that begs the biggest question: even if Andy finishes the house, will Jeanette actually like it?

To celebrate 20 years of Grand Designs, Kevin McCloud reveals his top five buildings from the show, revisiting the buildings and people who have most inspired him over 180 episodes.