Climb the Sydney Harbour Bridge

It's a long way down from the top of Sydney Harbour Bridge, but the view of the world's greatest harbour and the glittering city spread out below your feet is unbeatable – climbing the arch of Sydney's iconic bridge is a thrill like no other. It might look scary from ground level, but it's so safe that even kids as young as eight can do it. Before you go, BridgeClimb will get you kitted out with a climbing suit and a harness that is linked to a secure, static line. It's an easy walk, but has lots of steps. Sunrise, daytime, sunset and night-time climbs are available, as well as climbs that go just halfway if you're nervous about heights. Climbs can take anywhere from 1.5 to 3.5 hours, depending on the type of experience you choose, so give yourself plenty of time. Visiting Brisbane? You can also climb the Story Bridge.

Where is it?
BridgeClimb is located at 3 Cumberland Street in The Rocks. To get here, catch a ferry, bus or train to Circular Quay, then walk along George Street to the corner of Argyle Street. Take Argyle Street until you reach the Argyle Stairs. Head up the stairs to reach Cumberland Street and walk north to the entrance.

Do the world's highest dam abseil

If getting ready to step into the void on the world's highest commercial abseil doesn't get the adrenaline pumping, nothing will. The Gordon Dam in south-west Tasmania is several metres higher than the Sydney Harbour Bridge, and an abseiling adventure will have you descending 140 metres (459 feet) in one continuous drop. This is an extreme adventure that's not for the faint-hearted or those scared of heights, but if you're game, it’s a thrill that you'll find only in Australia. Tours are run from Hobart by Aardvark Adventures.

Where is it?
The Gordon Dam is located near Strathgordon, a 2.5-hour drive west of Hobart. You'll need to meet your tour guides at the dam in the morning, so consider staying overnight in the area. Pedder Wilderness Lodge is just a 15-minute drive from the dam and offers a range of beautiful accommodation and other hiking and adventure excursions.

Dive with great white sharks

Coming face to face with a great white shark with nothing between you and its giant jaws but steel mesh is an incomparable adrenaline rush, and only in Australia can you do this and swim with wild sea lions on the same trip. The waters off the southern tip of the Eyre Peninsula in South Australia are home to a large colony of endangered sea lions that love interacting with swimmers, so much so they are known as the "puppies of the sea". This is also the only place you can go shark cage diving in Australia. Intrepid divers often see sharks that are almost six metres (19.5 feet) long, though thankfully, not while they are swimming with sea lions. The cage is suspended just below the surface and you breathe through a "hookah", so you don’t need to be a certified diver. However, you do need a sense of adventure. Adventure Bay Charters and Calypso Star Charters run shark and sea lion tours from Port Lincoln.

Where is it?
Port Lincoln is on the Eyre Peninsula's east coast. The easiest way to get there is on a one-hour flight from Adelaide. Alternatively, it will take you just over seven hours to drive to Port Lincoln from Adelaide. If you're travelling between May and August, be sure to stop in at Whyalla to swim with giant cuttlefish and Tumby Bay for secluded beaches. 

Swim with whale sharks

Nothing is guaranteed to make you feel small like swimming with a 14-metre (46-foot) long, 15-tonne (16.5-ton) whale shark. But don't be put off by the name. These massive but harmless fish are truly the gentle giants of the deep. Ningaloo Reef is the only place in the world where the whale sharks are known to visit so close to the coast, every year. The whale sharks swim close to the surface, so even snorkellers can get near them. Whale shark season is from late April to early July, and a number of tours operate from both Coral Bay and Exmouth.

Where is it?
Ningaloo Reef is near Exmouth on Western Australia's Coral Coast, about 1,200 kilometres (745 miles) north of Perth. See all the highlights along the way with this ten-day itinerary or fly to Learmonth Airport (Qantas flies daily) and hire a car or a campervan locally. Integrity Coach Lines also travels from Perth to Exmouth.

Raft through an ancient rainforest

Rafting the Franklin, one of the world's last untamed rivers, is a magnificent wilderness adventure through deep gorges, drifting in tranquil pools one moment and navigating exhilarating rapids the next. It's a remote journey through some of the world's most awe-inspiring scenery, including rainforest and ancient huon pine forests. The season runs from October to April, and most trips take between five and ten days. Numerous rafting companies specialise in Franklin River expeditions, departing from Hobart and Launceston.

Where is it?
The Franklin River is located in south-west Tasmania. This area of the world is wild, rugged and still largely untouched by civilisation. Your chosen tour company will organise return transfers from your hotel in Hobart or Launceston. Daily flights are available to either city from both Sydney and Melbourne.

Walk through the sky

The Gold Coast is famous for its high rise towers, and you'll get a great view of them from the top of the beachside strip's tallest building. Even better, you won't be on the inside of the building, but the outside. At 270 metres (886 feet) high, the SkyPoint Climb to the summit of the Q1 Resort building is the ultimate high-altitude adventure. It's the highest external building climb in Australia. Attached to a safety harness, you step outside on to the launch platform on level 77 (240 metres, or 787 feet high) then climb to the top of the spire. If the stairs don’t take your breath away, the view certainly will.

Where is it?
The Gold Coast is a one-hour drive or shuttle bus ride from Brisbane. International flights fly directly into Brisbane Airport from many global hubs. Or, if you are travelling to the Gold Coast from within Australia, direct flights arrive at Gold Coast Airport in Coolangatta.

Valley of the Giants Tree Top Walk

The tall trees of southern Western Australia are among the tallest in the world, soaring up to 75 metres (246 feet) high. They are pretty big at ground level too, with some karri and tingle trees having a girth of more than 20 metres (66 feet). The best way to get a measure of just how vast these trees are is on the Tree Top Walk, a 420-metre (459-yard) long steel truss walkway that takes you up and over a deep, red tingle gully through the treetop canopy near the town of Denmark. Looking down from the walkway's highest point, 40 metres (132 feet) above the ground, you’ll see why they call this place the Valley of the Giants.

Where is it?
Denmark is a 4.5-hour drive from Perth, or you can fly to nearby Albany with Regional Express and hire a car for the 40-minute westward trip.