Last year, three million came for the hajj, a pilgrimage in the last month of the Islamic lunar calendar that is considered obligatory for every Muslim who can afford it; five million more came for the umrah, a minor pilgrimage that can be made for much of the year. And millions of Saudi citizens routinely pass through Mecca’s sacred sites as tourists. ... It is a transformation that has been underway since the late 1970s, when the wealth generated by the oil boom led Saudi monarchs to devise an ambitious plan to replace earlier Ottoman structures and to expand the Grand Mosque and its surroundings with Arab-style architecture. At a projected cost of $26.6 billion, the Saudi Binladen Group has led the efforts to increase the capacity of the Grand Mosque ... Throughout the history of Islam, no other ruler built in such proximity to the Kaaba; certainly none built anything to dwarf it. In luxury hotels like the Fairmont Makkah Clock Royal Tower and the Raffles Makkah Palace, views of the holiest site of Islam are marketed as the “Haram view” and “Kaaba view,” and a standard room can run anywhere from $1,500 to $2,700 a night during the hajj.

In 1609, Galileo wowed Venice’s big cheeses by letting them use his telescope to see ships way out at sea, a good two hours before their owners would see them enter the port. The Venetians were impressed (they doubled Galileo’s salary and gave him lifetime tenure at the University of Padua) because they immediately saw the huge financial and military advantages offered by this visionary device. A few hundred years later, we are on the cusp of an equally radical transformation in how information is gathered, analyzed and monetized. ... Seattle-based BlackSky Global is planning to launch six spacecraft; Terra Bella, a Google-Alphabet subsidiary, has two satellites in orbit and promises video that can “see objects up to the size of a car,” while Spire owns 17 orbiting satellites and plans to track ships in the world’s oceans. These and other upstarts are chasing imaging giants like DigitalGlobe, and Airbus, who have hundreds of millions of dollars of hardware floating miles above our heads. But no one has launched as fast and as often as Planet, a startup running out of an old gray warehouse in San Francisco’s Mission District. In a neighborhood filled mostly with vintage furniture stores, hip restaurants and coffee shops, Planet has 62 satellites in orbit, the world’s largest private collection, and by the end of the year it will have 100, enough that every nook, cranny and keyhole on Earth will get its own medium-resolution photo every single day. This avalanche of images will create an unprecedented database of the entire planet, one that can be used to stop forest fires and maybe even wars.

Reversing Paralysis: Scientists are making remarkable progress at using brain implants to restore the freedom of movement that spinal cord injuries take away.
Self-Driving Trucks: Tractor-trailers without a human at the wheel will soon barrel onto highways near you. What will this mean for the nation’s 1.7 million truck drivers?
Paying with Your Face: Face-detecting systems in China now authorize payments, provide access to facilities, and track down criminals. Will other countries follow?
Practical Quantum Computers: Advances at Google, Intel, and several research groups indicate that computers with previously unimaginable power are finally within reach.
The 360-Degree Selfie: Inexpensive cameras that make spherical images are opening a new era in photography and changing the way people share stories.
Hot Solar Cells: By converting heat to focused beams of light, a new solar device could create cheap and continuous power.
Gene Therapy 2.0: Scientists have solved fundamental problems that were holding back cures for rare hereditary disorders. Next we’ll see if the same approach can take on cancer, heart disease, and other common illnesses.
The Cell Atlas: Biology’s next mega-project will find out what we’re really made of.
Botnets of Things: The relentless push to add connectivity to home gadgets is creating dangerous side effects that figure to get even worse.
Reinforcement Learning: By experimenting, computers are figuring out how to do things that no programmer could teach them.