It's hard now to imagine that kind of travel and the daily tasks they simply took for granted. If a wagon axle broke, you had to stop and carve a new one. To cross a river, you sometimes had to build a raft.

Of course there were times, particularly when you travel, when it's very tough to leave the kids, particularly when they were very young. I would try to take them with me when I could just so they could experience and see a little bit of what a work day involved.

Book tours and research provide a lot of travel - too much, I sometimes think, but we do take vacations.

I love flying; I love aircraft, and you could say I've had a love affair with flight since I was a child. I travel a huge amount. I use airports, and as a pilot, I've flown in and out of airports thousands of times, so really, I have a fairly broad perspective.

That's the way both they and I travel sometimes. Pick road at random, and when it's time to pull over, you pull over and hope you can find a place to crash.

In all my wild mountaineering, I have enjoyed only one avalanche ride; and the start was so sudden, and the end came so soon, I thought but little of the danger that goes with this sort of travel, though one thinks fast at such times.

When I travel with my kids abroad, I am not myself, but I'm more a father who wants to protect them. Sometimes, I am even aggressive about certain things and get surprised seeing myself like that: for instance, when people want to take pictures of them. I am fine if they want to take my pictures, but they are not public property.

Without much money, I traveled to Argentina to see the meat industry, and after that, I wanted to travel to the United States, but I was refused a visa 5 or 6 times, but I never gave up.

I travel the world visiting global health programs as an ambassador for the global health organization, PSI, and sometimes the disconnect I see is truly striking: people can get cold Coca Cola, but far too infrequently malaria drugs; most own mobile phones, but don't have equal access to pre-natal care.

The biggest effect of travel on me is that it acts as a source of motivation. At times it makes me feel small, too. I want to visit more places.

I love to travel, but sometimes it's nice to stay in one place.

People who think about time travel stories sometimes think that going back in time would be fun because you would have all the information you needed to be much more astute than the people there, when the truth is of course you wouldn't.

Everything that happens is meant to be. It's meant to happen like that. But sometimes you don't know at the time that it's meant to be disaster.

I love the sensation of being out in the open air, far away from all the distractions of modern life. I will usually disappear for a couple of hours, and that time on my bike is quite sacred, as it's when I do all my serious thinking. Sometimes I will stop off at bikers' cafe and have a bacon sandwich.

If you're climbing the ladder of life, you go rung by rung, one step at a time. Don't look too far up, set your goals high but take one step at a time. Sometimes you don't think you're progressing until you step back and see how high you've really gone.

The time that I have on this earth should just be filled with good times.

Sometimes you have to play a long time to be able to play like yourself.

Enjoy your time in public service. It may well be one of the most interesting and challenging times of your life.

Sometimes I wish that I could go into a time machine right now and just look at my self and say, 'Calm down. Things are gonna be fine. Things are gonna be all great. Just relax.'

You've got to make tough decisions, sometimes unpopular decisions... Whatever it is, if it's the right move at the right time, you've got to be also willing to make mistakes.

I regret those times when I've chosen the dark side. I've wasted enough time not being happy.

Tough times never last, but tough people do.

Time sometimes flies like a bird, sometimes crawls like a snail; but a man is happiest when he does not even notice whether it passes swiftly or slowly.

Twitter, I always say is the drunk uncle of my personality, because I say some stuff sometimes that, you know that drunk uncle at the Thanksgiving table, he starts rambling on about, that he shouldn't have said so sometimes I do that.