A Walk Around the Block Summary

1-Sentence-Summary: A Walk Around the Block is a beautiful, local-neighborhood exploration of where “the things that sustain us,” aka our infrastructure, comes from, shedding light on 26 everyday wonders we now take for granted but that took decades, sometimes millennia, to reach the masses and change history.

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A Walk Around the Block Summary

As he turned on the tap one cold January morning, Spike Carlsen expected the same thing he always expects: running water. This time? No luck. His water service line was frozen. It took two days for someone to fix it — and six weeks of constantly running water to not re-freeze.

How could Minnesota, the “Land of 10,000 Lakes,” not have running water in the 21st century? Then again, Carlsen does live in Stillwater…the irony! More importantly, however, where did his water come from in the first place?

As an author, he had read books about climbing Mount Everest and written ones about violin makers in Italy. Yet he knew nothing about everyday infrastructure.

A Walk Around the Block: Stoplight Secrets, Mischievous Squirrels, Manhole Mysteries & Other Stuff You See Every Day (And Know Nothing About) describes Carlsen’s exploration of “the things that sustain us.” From what’s going into your house to what goes out and the surfaces, nature, and man-made tools that surround it, Carlsen describes 26 everyday wonders.

Here are 3 of them to open your eyes and make you appreciate the mundane:

  1. Messages went from taking 12 days to less than a millisecond to reach their recipient.
  2. The Romans perfected concrete, but then we lost its formula for 1,000 years.
  3. There are 7 secrets of traffic lights, a technology that’s expensive but saves more money and lives than it costs.

Let’s take a walk around the block!

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Lesson 1: Modern phones have increased the speed of information from 1,000,000 seconds to 0.0053 seconds, a mind-boggling 200 million times-improvement.

When Carlsen received the notification on his phone that Justin Bieber had peed into a mop bucket, the information traveled 1,000 miles within a millisecond of being published. Here’s how long that same journey would have taken using previous means of transport:

  1. Foot messenger: 11 days, 20 hours. And that’s at record pace. Equates to 1,022,400 seconds.
  2. Horseback: 3 days, 21 hours.
  3. Signal telegraphy: 1 day, 12 hours. Think fires being lit along the Great Wall of China.
  4. Messenger pigeon: 1 day, 10 hours.
  5. Optical telegraph: 4 hours, 10 minutes. These used flags and shutters to send coded words across a distance.
  6. Telegraph: 3 minutes.
  7. Switchboard telephone: 40 seconds.
  8. Cell phone: 0.0053 seconds.

From foot messenger to cell phone, information now travels 200 million times faster, from 2 weeks to instantaneous. Even just from switchboard operators in the 1930s, waiting times have dropped by another 99.98%.

It’s hard to comprehend how far we’ve come from tin can phones, clicking telegraphs, and people plugging in and out cables. It’s worth stopping every now and then and appreciating how fast your phone does what it does. Don’t take it for granted.

Lesson 2: Concrete is everywhere, but after the Romans perfected it, the formula was lost for 1,000 years.

In the 2010 Haiti earthquake, nearly 300,000 man-made structures collapsed — and buried more than 100,000 people beneath them. The reason? In many cases, badly mixed concrete.

“Concrete constitutes half of everything we build,” Carlsen explains. The material, which is different from lime-based cement (it has added sand, stone, and/or aggregate), was first devised up to 10,000 years ago. Today, we produce more than one ton per person alive each year. Only water can beat that kind of consumption.

From roads to sidewalks to garages and buildings, concrete is everywhere. Given its wide availability, cheap components, and high strength and durability, it’s unlikely we’ll completely replace it any time soon — even though it causes some 4-8% of all CO2 emissions. However, self-healing and self-cleaning concrete variants are in the works, and over 140 million tons are recycled each year.

Who do we have to thank for this miracle? Largely, the Romans. “The Pantheon, built around 100 CE, continues to hold the record as having the world’s largest unreinforced concrete dome,” Carlsen shares. The structure’s thickness varies from 7 to 1 meter, and it has a 30-foot-diameter circular opening at the top, all in one giant, single, 5,000-ton piece!

After perfecting the concrete formula over 700 years, sadly, the recipe was lost when the Roman Empire collapsed. Only in 1414 did someone rediscover it in a copy of Vitruvius’s On Architecture in a Swiss monastery.

The next time you walk on the sidewalk, remember: Concrete could have easily stayed lost and forgotten. Now if only we could find a way to get good mixtures everywhere, so that no one needs to worry about their roof falling on their head.

Lesson 3: Traffic lights cost a lot but save even more, and there are 7 things you likely don’t know about them.

When US car production skyrocketed from 2,500 per year to over 500,000 in the early 20th century, so did accidents. In 1913, 34 drivers died for every 10,000 cars on the road. Today, it’s only 1.5. Enter: The traffic light.

The world’s first traffic light went live in 1868, in London. Semaphore arms by day, a gas-powered light at night. Unfortunately, it exploded, and the event prevented development for decades. Here are 7 more interesting traffic light tidbits:

  1. The 10% rule: Divide the speed limit by 10 to get an estimate of how long the green phase will last, though it’s usually at least 3 seconds anywhere.
  2. The all-red phase: There’s a precautionary phase in which lights in all directions are red, usually from 1.5-3 seconds.
  3. Forever = 4 minutes: 1.5-2.5 minutes is the average cycle length. Long lights take 4+ minutes. Waiting can feel like forever but is actually not that long.
  4. Triggers needed: Induction triggers in the pavement and stop stripes need metal to fire and activate the light cycle. Bicycles often don’t trigger it and wait longer as a result.
  5. Foot seconds: Crosswalks offer 4-7 seconds of starting time and 1 extra second per 3.5 feet of walking distance, meaning you get at least 5-10 seconds to cross any street as a pedestrian.
  6. Bogus buttons: Most pedestrian crossing buttons are placebos. But the ones that do work can give more time depending how long you press them to account for children, seniors, etc.
  7. Green for guardian angels: Some traffic lights recognize the strobe lights of an ambulance and extend their green phase accordingly, which increases response times and reduces crashes.

“Installing a set of traffic lights can cost from $150,000 to $500,000,” Carlsen reports. But it saves a lot more — both lives and money. For every dollar the Minnesota Department of Transportation spends on traffic control, the public saves $40 to $200.

Green lights are important in traffic and in life — but even red ones have their purpose. Chill out the next time traffic stops, and instead of venting, take a second to appreciate the complex dance that is traffic management.

A Walk Around the Block Review

A Walk Around the Block is a profound book with a simple premise: Get to know the world you interact with every day, and you’ll never see it the same way as a result. A beautiful work, written with joy, sending an important message. Give it a go!

Who would I recommend our A Walk Around the Block summary to?

The 17-year-old, curious first-time driver, the 42-year-old housewife lost in everyday business, and anyone who doesn’t have a clue how the electricity in their house reaches its sockets.

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Niklas Göke

Niklas Göke is an author and writer whose work has attracted tens of millions of readers to date. He is also the founder and CEO of Four Minute Books, a collection of over 1,000 free book summaries teaching readers 3 valuable lessons in just 4 minutes each. Born and raised in Germany, Nik also holds a Bachelor’s Degree in Business Administration & Engineering from KIT Karlsruhe and a Master’s Degree in Management & Technology from the Technical University of Munich. He lives in Munich and enjoys a great slice of salami pizza almost as much as reading — or writing — the next book — or book summary, of course!