The Christchurch Earthquake: When A City Falls.

The Christchurch Earthquake: When A City Falls.

When a City Falls: The Christchurch Earthquake, SBS One, 8.30pm

THIS documentary is, quite simply, devastating. It opens with director Gerard Smyth admitting he could never have planned the outcome. Begun as a document of the 2010 earthquake in Christchurch that measured 7.1 without taking a life, it is a rough-and-ready account of the impact and results that feels nearly finished before the 6.3-magnitude earthquake of 2011 strikes, with its terrible toll of 185 fatalities. There is something captivating about the journey from panic and raw grief to hope and resilience that is caught in this before-and-after snapshot, mostly because of the single, subjective point of view that Smyth infuses the film with as he walks the streets. This is the perfect documentary to capture this tragedy.

The Block: All Stars, Channel Nine, 7pm

LOOK, it's not a clip show, and it's not a masterclass, so we have no real right to complain about a new episode of a reality show on a Friday night, even if the drama tonight revolves around 24-hour bugs, lost mobile phones and urinals. It's all about alliteration as Dan and Dani deal with diarrhoea. Dan has a 24-hour bug and really just needs to rest, so thankfully a camera crew are on hand to interrupt him every couple of minutes to check how that's going, while Dani is faced with the dilemma of what to do with Snoop. Meanwhile, Adam the electrician has dropped his mobile phone down the inside of Phil and Amity's wall, and such is the action-packed nature of The Block on a Friday evening that this is described as ''high drama''. Then Mark and Duncan's urinal flushes and it's really all happening. Me, I'm just wondering if you can't send the dog down the wall after the phone.

Better Homes and Gardens, Channel Seven, 7.30pm

IT'S prime-time flagship crossover as Joh visits X Factor judge Guy Sebastian and his family at their beachside getaway. Guy is his usual shiningly contented self and, upon spending any amount of time in his home, it's easy to see why. Elsewhere, there is a bonanza of believe-it-or-not items in the form of houses built into cliffs, one-bowl lemon lime cakes and surfboards made into tables. By the time Harry has introduced some ''peculiar pets'', you'll need a drink and a lie down. Actually, you might want the drink beforehand.