Let’s Time-Travel Through the 15 Most Relentless Building Projects Ever

Build Time: 1386 to 1965, yep, 579 years of slow-mo construction.

This cathedral? A mega maze of statues, marble, and design tweaks. Every generation thought, “Let’s add more!” so it dragged on forever.

Even Napoleon got starstruck and asked for the pace to speed up to host his big coronation in 1805. Officially done in ’65, it’s still the shiny crown jewel of Milan.

Build Time: 1344 to 1929, a whopping 585 years.

Think wars, plagues, fires, and political drama - this cathedral survived them all, slowly creeping toward completion.

Its style is a cool mash-up of fancy medieval and fancy Art Nouveau, with dazzling stained glass designed by a famous local artist. Visitors today get to see over 500 years of architectural gossip all wrapped in one building.

Build Time: Roughly 1113 to 1150 A.D., get this - just 37 years to build the main part.

Compared to our other mega-slows, Angkor Wat zipped along! But its story doesn’t stop there - centuries of temple expansions and complex waterworks kept it evolving.

Covering a humongous 400 acres and packed with 2,000 carvings, it’s the world’s biggest religious monument that still looks authentic and gorgeous.

Build Time: 1220 to 1472, for 252 years of ups and downs.

This cathedral kept switching plans as Gothic style evolved, plus it battled fires and political messes.

Its massive Great East Window is one of the biggest medieval stained-glass showcases, and it took generations to piece even that together.

Today, it’s one of the UK's top religious landmarks, kept shiny by devoted donors.

Build Time: 1248 to 1880, the world’s ultimate on-hold project with 632 years on the clock.

Started to protect some fancy relics, it stopped when the money tanked and politics got wild in the 1500s. For centuries, it basically just stood there.

In the 1800s, builders dusted off the old blueprints and finished it up, and it even became the tallest building in the world for a while.

Now it’s a top tourist hotspot and UNESCO champ.

Build Time: Roughly 2589 to 2504 BC, about 85 years of ancient hustle.

These iconic pyramids show off Egypt’s power, built by moving insane amounts of heavy stones - no machines, just muscle.

The Great Pyramid was Earth’s tallest building for nearly 4,000 years, accurately aligned to the compass points. Archaeologists keep discovering secret chambers inside for extra mystery points.

Build Time: 1882 to 2026, finally done after 144 years.

Gaudí’s dream church turned into an epic saga. He died a long time ago, and a civil war wrecked his plans, so folks had to piece it back together like a giant puzzle.

The final build beams with towers, tree-like columns, and sunshine-colored stained glass.

2026 marked its official grand finale - or at least the main one!

Build Time: From 3rd century BC all the way to the 1600s - over 2,000 years of patching and expanding.

After tons of invasions, dynasties kept beefing up this mega wall. It’s not one wall but many linked sections, and it’s HUGE.

Up to 800,000 workers, including soldiers and prisoners, chipped in over the centuries.

Fun fact: it’s NOT visible from space with the naked eye but still a mind-blowing engineering marvel.

Build Time: Slowly built from 3100 BC to 1600 BC, about 1,500 years.

Not built in one go - Stonehenge was a slow project with earth mounds, giant stones hauled from Wales, and more bits added over centuries.

It’s perfectly aligned with the summer solstice sunrise, so ancient astronomers were definitely on their game.

Now a must-see spot and a World Heritage Site, it’s a real head-scratcher in the best way.

Build Time: 8th to 9th century, about 100 years of temple wizardry.

Built with millions of volcanic stones, this temple got buried under jungle and lava before being rediscovered.

With 2,600 fancy relief panels and hundreds of Buddha statues, it’s basically a giant spiritual mandala you can walk around.

Thanks to 20th-century restoration heroes, it’s still standing strong today.

Build Time: 1869 to 1892, 23 years of castle-building drama.

King Ludwig II decided to craft his own fairytale castle, but his perfectionism slowed things down and raised the bill.

Even though he died before it finished, the castle inspired Disney’s Sleeping Beauty castle.

Medieval vibes but with fancy 19th-century tech like running water and central heating.

Some say it’s still “technically unfinished,” but it’s gorgeous either way.

Build Time: 1881 to 1914, 33 years of muddy, mosquito-filled madness.

First the French tried, but the mountains, rain, and deadly diseases like malaria nearly shut it down.

When the U.S. took over in 1904, they revamped the plans, tackled the bugs, and built those famous locks.

The canal changed global shipping forever, letting ships skip the long trip around South America.

It even led to new towns, railways, and lakes just to keep it running.

Build Time: 1984 to… still going? 42+ years and counting.

Romania’s dictator dreamed big with this mega palace, meant to shout 'socialism rocks.'

It’s massive - heaviest historic building, thousands of rooms, tunnels, even a nuclear bunker.

Budget woes and its mind-boggling size slowed things way down.

Some parts are still unfinished, so this palace might be the forever project of all forever projects.

Build Time: 1892 to now, over 130 years and still counting.

This giant New York cathedral faced remodeling madness, money troubles, and even a big fire in 2001 that slowed things down.

Its mix of Romanesque and Gothic styles is because architects kept changing their minds mid-build.

Though not quite finished, it’s been welcoming visitors and hosting events for decades.

Build Time: 1987 to now, 39 years and it’s still not done.

This futuristic pyramid started huge and shiny but stalled hard in the ’90s during North Korea’s economic crisis.

It’s one of the tallest empty buildings out there, looming over Pyongyang like a giant concrete mystery.

Rumor has it much of the inside is unfinished, so its future remains a big question mark.