Manholes connect underground sewer and water drain pipes

Japan is home to intricately designed region-specific manhole covers

The country's eye-catching sewer covers were a form of brand rehabilitation, intended to change people's perceptions of the sewer. Additionally, they're easy to see at night, making firefighters' nighttime duties a bit easier.

The simplicity of immersed tube tunnels

Tunnels have traditionally bored holes through the earth below the water. On the other hand, immersed tube tunnels connect hollow, massive sections in trenches along the floor of the body of water. Each section is built on land, floated to the site, submerged, and connected. This method saves money by reducing expensive underground work, and it preserves an area's aesthetic appearance.

The sewage of New York City

Residents of the five boroughs of New York produce 1.3 billion gallons of wastewater everyday. Seventy miles of sewer pipes, first built in the mid-1800s, feed the sewage to 14 wastewater treatment and recovery plants where the waste is treated back to viable, drinkable water. See what shouldn't go down the toilet here.

Sinkholes form when underground cavities cause the surface above to collapse

These openings are typically carved by acidic water, which often forms in limestone-rich areas. However, leaking pipes, groundwater removal and extreme weather or geological activity increases the frequency of sinkhole appearances.

Modern landfills use layered liners, leachate systems, and gas monitors to safely contain waste

Today, landfill engineering is far more complex than a hole in the ground, which was largely the system cities used less than a century ago. This video explains how it actually works.

Disney World's Magic Kingdom includes an underground utilidor

Walt Disney viewed everything happening in his parks as a performance and didn't like it when that performance was disrupted by necessary aspects of the park's maintenance, like trash collection. With Florida's Disney World, the company corrected that problem by building a massive area underneath the park to be used as a "backstage."

Key components of a joint: bones, cartilage, ligaments, tendons, and fluid

A human joint is any place in the human body where two bones connect. This junction allows for movement, but is prone to breakdown and pain. This nine-minute video explains normal joint anatomy and function, with particular attention to the different types of motion each joint facilitates.

Fire engines are among the most complex vehicles on the road

These vehicles are purpose-built to carry water, foam, hoses, ladders, and lifesaving equipment to a scene in minutes. This animated video pulls apart every system inside a pumper truck, showing exactly how the machinery that fights fires actually works.

View major global infrastructure, including power plants, fuel lines, and water pumping stations

The Open Infrastructure Map displays data from the OpenStreetMap database, which aggregates information from freely licensed geodata sources, surveys, and photographic and satellite imagery. It also displays power lines, generators, substations, various chemical pipelines, telecommunications towers, data centers, and more in daytime and nighttime maps.

Windmills can be designed to pump groundwater for irrigation or land drainage

A gearbox within the windmill converts the windmill's rotation into the vertical motion of a piston that pushes water up a pipe. It also drives the rotation of an Archimedes screw to move water to higher elevations.

O-rings contain fluid within a system

These donut-shaped components, typically made of rubber, block the escape of liquids and gases in low-pressure systems by forming a seal when compressed within a groove. In high-pressure systems, the O-ring is forced into a gap, blocking any leakage.

Learn why electrical substations are needed to provide safe electricity with minimal energy loss

These typically fenced-off facilities with steel boxes or cylinders topped with cone-like caps house circuit breakers, fuses, and switches that can isolate sections of the grid to prevent electrical failures from spreading. Substations use transformers to modify electrical voltage and are customized to the generation, transmission, and distribution networks they interconnect.

How to maintain a healthy gut

Approximately 40 trillion microbes reside in the human gut, forming a unique microbiome, containing hundreds of millions of neurons in what is often called a "mini-brain". A healthy gut is characterized by an effective mucus-lined barrier that prevents unwanted substances from entering the bloodstream. So how do you attain such an ideal gut? This guide outlines a healthy approach to protecting your gut.

Smart cities support interdepartmental goals by facilitating shared infrastructure

Instead of working in isolation, municipal departments can share data, such as lighting and telecom needs, seamlessly and collaborate to solve larger-scale problems together. Integrating public feedback systems can further improve city services and sustainability.

The fish doorbell letting people help spawning fish

Utrecht, a city in central Netherlands, has implemented an innovative "fish doorbell" system at a river lock to assist migrating fish during their spring journey to spawning areas. This unique setup allows online viewers to participate in helping fish navigate through the locks. An underwater camera is installed at the Weerdsluis lock, streaming live video to a dedicated website, where viewers may press a digital button when they see a fish.

Cutting mold off your food does not make it safe to eat

Mold is a type of fungus, but not all fungi are molds. This video explains the value of mold, mold anatomy, health concerns around encountering and eating mold, and why mold is found all around us.

How the Domain Name System works and how it provides a directory for the internet

DNS translates domain names, such as join1440.com, into numerical IP addresses, such as 192.0.2.1, which computer systems use to determine what content a user is looking for across the World Wide Web, making navigation easier for the vast majority of users. Web outages can occur if the DNS servers making these translations become inaccessible.

Money 'mules' don't always know they are laundering money

Money mules are anyone who receives money in a laundering scheme and then sends it forward, either to another company or to a financial institution. While some money mules—often called smurfs—actually work with criminals laundering money, getting someone to receive and then send money has become a popular scam.

Why are coral reefs important?

Coral reefs are vital ecosystems that millions of people and countless species depend on. This two-minute video from London's Natural History Museum looks at the ecological and economic significance of coral reefs, including their biodiversity and...

Visualize the purpose of stomata in photosynthesis

These openings on the underside of leaves can be opened and closed by specialized guard cells to regulate the movement of carbon dioxide into and oxygen out of cells, thus impacting the rate of photosynthesis. At night, when the light-dependent reactions in photosynthesis are not possible, the stomata close to prevent the plant from losing water through transpiration.

Roman roads have lasted for millennia and were key to its military might

Known for their almost absurd straightness, Roman roads connected the empire's armies, messengers, and traders as imperial administrators sought to keep down rebellion and build up Roman wealth. Rome's highways were expertly engineered, well-patrolled, and easy to navigate.

A history of manicules, or the little hands in books and posters

Manicules are illustrated hands used in many contexts to point something out, whether by medieval readers to highlight passages or in 19th-century advertising. The hands have a quirky, persistent history, showing up over hundreds of years in everything from Petrarch's books to computer cursors and the US Postal Service's "Return to Sender" stamp.

Investors trading their municipal bonds can't use the same method to purchase them

Instead, they’ll have to go through the secondary market, which has its own set of rules and steps to follow. An illustrated, explanatory video can help you learn how to sell your municipal bonds for the best market value.

Horace Mann was America’s champion of free, standardized public schooling

Horace Mann (1796–1859), Massachusetts Secretary of Education from 1837–1848, led the 19th-century Common School Movement. He established state boards, founded normal schools for teacher training, and urged universal, nonsectarian, tax-funded education. His reforms became national models.

Pig heart valves have been placed in humans since 1965

The first successful use of a pig heart valve in a human was reported in 1965. This 2015 video details why humans have been able to use pig animal valves for so long with good results and how that differs from what's needed for whole organ transplants.

In 1963, a basement renovation in Turkey revealed a passageway to a hidden, multilevel underground city that once housed as many as 20,000 people

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

The American Society of Civil Engineers' infrastructure report card gave the US a C in 2025, its highest grade since the project launched in 1998.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

In its famous catalog, Sears sold $600 DIY house kits from 1908 through the 1940s, resulting in an estimated 100,000 'Sears and Roebuck homes.'

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Existentialist writer Jean-Paul Sartre coined the famous phrase 'Hell is—other people' in his play 'No Exit'

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

Walt Disney's early film 'Alice's Wonderland' was a groundbreaking innovation in the silent film era