There is a trapdoor on Christ's right shoulder.

To mount the steps and slowly, fearfully peer out is to see the world through the eyes of a bird, or even a god. Far below, white blocks of flats and offices cluster among folds of tropical green.

Down there are the poor in the favelas, the rich in the luxury high-rise apartments, the homeless, the famous football stadiums and Guanabara bay with its scattered islands and boats. Beyond the sands of Copacabana and Ipanema, the limitless Atlantic ocean.

To the left, standing twice a man's height, is the slightly bowed head of Christ, also looking down on the beauty of the city.

But unlike the forests or the ocean, this statue was the work of man and will not last for ever. Close up, the toll of 83 years of weathering is starkly apparent.

Unnoticed by the 5,000 who visit the landmark every day - and see it only from a distance - the surface is a patchwork of worn mosaic tiles resembling the skin of an aged reptile.

Lightning storms have been chipping away at it. In January, two direct hits in eight days blasted off a middle fingertip and scorched the back of the head, sparking a race to patch up Rio's favourite picture-postcard scene before the World Cup in June.

Such is the statue's popularity that even at 8am there is a babble of tourists taking photographs and enjoying the view. For them, the only sign of anything wrong is the scaffolding that leads up the 8m (26ft) pedestal to a discreet entrance in the hem of the cloak.

If the statue had a right ankle, the door reserved for workers would open into it. Once inside, the hubbub disappears.

There is little natural light and only a few bare bulbs. Flights of open stairs make their way up through the centre, between the criss-crossed concrete supports that give the statue its strength.

A thick skin of reinforced concrete means the inside is cool, despite the summer heat outside.

Climbing up, a number is crudely painted on the wall of each of the 12 floors in what feels like an abandoned, dusty warehouse.

There is no sign that this is the inside of Christ the Redeemer until an upper level, where a roughly shaped heart bulges from the inside of the chest. It is covered in the same stone mosaic as the outside of the statue - where the outline of the heart can also be seen - the only delicate detail in an interior that's otherwise rough around the edges.

From the top of the last set of stairs, a vertical steel ladder leads to a tunnel in the statue's arm. A dark, narrow passageway then stretches all the way to the fingers.

The only way to inspect the damage caused by the recent lightning strikes is to go out - through the top of the 30m-high statue.

The workers who crawl out of the holes in the arms, shoulders or head use ropes to tether them as they abseil down the torso or inch along the 28m-span of the arms, the city spreading out before them, far below.