From the top of Everest to the depths of the Mariana trench – what’s it really like?

Is there any way to compare climbing to the top of the world and summiting Mount Everest, with going to the very lowest place on Earth, the depths of the Mariana Trench?

Both grand adventures certainly, but how does it feel?

Victor and Vanessa after the dive Photo Credit Enrique Alvarez
Victor Viscovo and Vanessa O’Brien, the first women to reach the top and the bottom of the world. Photo: Enrique Alvarez

Vanessa O’Brien is truly unique, having gone from Wall Street into a world of adventure – with a list of accomplishments that includes being the fastest woman to complete the Explorers Grand Slam, (the 7 summits and reaching both North and South Poles), in 295 days, and also being the first American – and as she also holds British citizenship, the first British woman to successfully climb up and get down K2.

While she has recently been covered in a host of press, from the New York Times to Forbes to the BBC, I still had a few questions I was curious about. And here is what she had to say….

  • Is there any way to compare touching the lowest point on Earth to touching the highest point on Earth? What did it feel like? 


Aha… my favourite question!

I saw the process of a submersible dive very similar to the process of mountaineering – cramped quarters (submarine vs tent), and both take place in the cold, in the dark, with compromised communications. They both focus on a ‘summit’ moment and both are in a low natural oxygen environment.  Both deep oceans and high-altitude peaks involve high risk/return trade-offs, are both caused by plate tectonics, are impacted by climate change, head directionally ‘vertical’, and could get you wet (precipitation vs condensation). :-). 


The lowest point we can reach on our Earth. Perhaps a bit Jules Vernesque? Certainly other-worldly. Photo: Vanessa O’Brien
SkiingToSouthPoleVoBPhoto:Mike Hamill
En-route to the South Pole. Another monochromatic colour palette, also pretty flat. Well insulated from the environment.  Photo: Mike Hamill 


Having said that… if one is lucky with the weather at the top of a mountain, the views can be spectacular and the sense of accomplishment second to none. 

With a submersible dive it felt more like visiting another plane. I was looking out of portholes smaller than my make-up mirror, studying the sediment on the seabed floor certain I saw something move.  Hearing the safety checks (‘Roger… this is mission control…’) every fifteen minutes, and watching the sonar spin round checking for any signs of the nearby lander that was recently pinged by the sub. 

I felt more like a visitor to a secret place. Once I had shook the sense of wonder I began to focus on my tasks: observing, mapping and searching for rocks to collect.

  1. Lowest, highest, as well as North Pole, South Pole. A most memorable moment from each? 

Most memorable moment on Lowest was having all the batteries fail on the starboard side of the submersible. 

There was never a moment of panic or fear despite my lack of mechanical or engineering skills. I simply thought logically and talked it through with Victor (who I am sure has these things) to look for solutions – could the port batteries ‘power up the starboard’ batteries?  If we shut off all power would the batteries recharge?  As we were heading in a starboard direction, could we turn 180 degrees and use the port thrusters to complete the transect?  All of these turn out to be possible if there isn’t something else wrong, always a possibility. 

Everest, South summit, sunrise
The first hint of sun, dawn from just below the Summit, Everest.

Most memorable moment on Highest was waiting for my Everest team who had all spent the night at Camp 4 to come down to Camp 2 the next day.

I was the only one who made it down to Camp 2 after the summit. When the team arrived, one member said he couldn’t feel the toes on his right foot.  I remember reading Ed Webster’s book at the time and there was lots of frostbite. I immediately went to work pulling his socks off, soaking his feet in lukewarm water, and calling the Himalayan Rescue Service (HRA) for a helicopter. 

What I learned is how important communications are because while both of his feet looked exactly the same (no blisters or any visual signs that something was wrong), he went on to lose all the toes on his right foot.

North Pole Robert Mads Anderson Antonovs Over the Arctic
The North Pole, it’s down there somewhere, moving every minute with the ice. Skiing there not the gentlest of journeys. Photo: Robert Anderson from Antonovs over the Arctic

Most memorable moment at the North Pole was first realizing it is the coldest place on the planet, and second, taking the Red Cross flag with me, having met the Red Cross just two nights before leaving Boston.  When I returned to Svalbard, I saw the Boston Marathon bombing had taken place during our visit to the North Pole. 

The Red Cross played such a heroic role helping the hundreds that were maimed, I dedicated the North Pole flag to those who helped save lives during the Boston Marathon who I felt were more heroic than me. I would later run the Boston Marathon in 2017 to help them raise money.

Most memorable moment on the South Pole was ending up being split in two teams and being led by a man named Scott. Keeping with the polar theme, our team arrived at the South Pole first and we found ourselves spending the night at the South Pole which was pretty wild.  We were granted a tour of the Amundsen-Scott South Pole Research Centre and heard all about the scientific projects being conducted there.

I remember how desperately we wanted to sit in the canteen and have a cup of coffee, but the research station would only allow us into their store to buy things.  Fair enough – we had our passports stamped for the ‘South Pole’ and bought some ‘South Pole’ mugs.  Who knew one could go shopping at the South Pole?


  • I haven’t read much on dangers, but from what I know from simply diving, going that deep must have some very dangerous elements? And perhaps fears? 


While people are quick to tell you how few ‘manned’ submersible dives take place –Walsh/Piccard (1960), Cameron (2012), Vescovo (2019) – there have been a few more unmanned dives using remotely operated vehicles (ROVs).  One of my favourite stories was a ROV called Nereus (you won’t be surprised to learn Greek God names are popular), that was described as suffering a  “catastrophic implosion” after surface debris was found near the Kermadec Trench, north east of New Zealand after operating some 10km (6.2 miles) down.

So, pressure is the biggest danger.  However, most people can’t imagine one jumbo jet on top of themselves, much less 292.  I get it. I’ve been trying to find a way to capture the force of this pressure, to capture people’s imaginations.  The best I have been able to come up with is to compare the pressure at Challenger Deep, which is 16,000 psi (pounds per square inch) to a Remington Model 870 12-gauge barrel shotgun ,with a 3-inch shell, that provides a mean average of 19,800 psi proofing for its’ barrels. I think it is fair to say that will kill you.

Outside of pressure, it helps not to be claustrophobic and not to panic when things go wrong. Things are bound to go wrong because… what is that simple phrase… oh yes, electricity and water don’t mix.  That probably explains all the electricians on board the mothership!  It probably also helps to have a good foundation in faith, any faith really, to take a load off.  I carried five rosaries from Rome, so one of them had work in a bind.


  • What was the celebratory drink when you got home and saw Jonathan (Vanessa’s ever so supportive and patient husband)


Jonathan was adorable. I arrived back in New York after three eight-hour flights.  It was a stopover before I went back to London.  He suggested Champagne and at first, I said no. 

Then I thought about it, and said, ‘Go on, then.’ I then gave him one of the rosaries and a Styrofoam cup I had shrunk, and he said, ‘that’s it?’.  There is no shopping in the middle of the Western Pacific Ocean, I’m afraid.

Shrunken Cups VoB
What happens to a styrofoam cup that goes 10 km. under the sea – a bit compressed. Photo: Vanessa O’Brien

I’ve been fortunate to have an early peruse through Vanessa’s upcoming book, To the Greatest Heights – a highly worthwhile read that will be out soon and that you can get on the list and pre-order now.

The Challenger Deep coin. Photo: Vanessa O’Brien