Downe, England ? The house that helped rock the world is spacious but not grand. It sits on a country lane in the south of England, at the edge of a tranquil meadow recently whitewashed by an unusual snowfall.

Inside, the great scientist worked with inexhaustible patience in his Victorian study, staring for hours at specimens through a microscope or pondering the riddle of life. In a black armchair specially fitted with wheels, Charles Darwin wrote “On the Origin of Species,” the book that forever changed the way we look at the world around us — and at ourselves.

Ubiquitous celebration

For 40 years, Down House was the perfect place for Darwin to think, write and enjoy family life out of the spotlight.

“The country is extraordinarily rural and quiet, with narrow lanes and high hedges and hardly any ruts,” Darwin wrote. “It is really surprising to think London is only 16 miles off.”

But so much for retiring from public view. Today, 200 years after his birth on Feb. 12, 1809, Darwin seems to be everywhere in his native land.

His bushy-bearded face graces numerous television programs exploring the impact of his ideas. Prominent Britons dissect his life and times on the radio. The city of Shrewsbury, Darwin’s birthplace, is lighting up buildings at night with huge projected images and films relating to its most famous son.

Libraries, zoos, art galleries, choral groups, universities, museums and, a little ironically, churches all own a piece of the extravaganza celebrating Darwin’s bicentennial, a yearlong series of 300 events that make up one of the most extensive national commemorations of a single person ever to be held in this country.

‘Biggest idea in science’

That may only be fitting for someone whose revolutionary theory of how life evolved leaped over the boundaries of pure science and into so many other spheres — politics, religion, economics, the arts.

“It’s difficult to overstate how pervasive Darwin’s work is,” said Robert M. Bloomfield, coordinator of the umbrella organization Darwin200 and head of special projects at London’s Natural History Museum. “He undoubtedly produced the biggest idea in science in the 19th century and, some people say, of all time. Because when you question your relationship to nature, you question everything.”

A recent editorial by The Times of London went so far as to argue this: “Darwin is not merely a man of his time. The extent of his achievement gives him a plausible claim to be counted the greatest figure in this nation’s history.”

Less controversy at home

That a scientist whose ideas still rile conservative religious groups can be so effusively feted is a testament to how secular Britain is, at least in the public square.

There have been few hiccups of protest over the attention being lavished on Darwin or the money spent on ballyhooing his legacy.

“It isn’t polarized like it is in the U.S.,” Bloomfield said. “There are people who rant on the interplay between science and faith, but it’s not the same sort of political debate in the U.K.”

Still, even the critically acclaimed “Darwin: Big Idea, Big Exhibition” at Bloomfield’s museum gives a nod to the controversies spawned by the concept of evolution through natural selection. Under the heading “Sticker Shock,” a biology textbook from Georgia bears a warning label mandated by the local education board: “Evolution is a theory, not a fact.” A short video also addresses the friction between Darwinism and religion.

But the thrust of the exhibition is the evolution of Darwin’s own thinking, how the seed of a blockbuster idea was planted and nourished over a long period.

Tree of Life

Crucial to that was his five-year voyage around the world on the Beagle, which launched in 1831 and brought the budding naturalist to exotic destinations full of creatures he had never heard of, whose variety and subtle gradations set his mind racing.

In a display case lies the Holy Grail of Darwiniana: the red notebook Darwin kept containing his famous drawing of the “Tree of Life,” on which he mapped out the development of different forms of life from a common primordial root. Modestly written at the top of the page are the words: “I think.”

As someone who once entertained the ambition of becoming a country parson, Darwin knew the outrage his theory would trigger in a society that largely clung to the biblical view of creation. Voicing his opinions aloud was, he confided to a friend, like “confessing a murder.”

‘Life goes on’

Perhaps that made him value his quiet country life all the more and the temple of domesticity he built with his wife, Emma, in the village of Downe. (The village added an “E” to its name before the Darwins arrived, but the couple never bothered to change the spelling of Down House.)

The home has undergone a three-month, $1.3 million makeover for the bicentennial and is to reopen to local residents on Darwin’s birthday, today, and the general public Friday.

By all accounts, Darwin was an indulgent, loving father to 10 children, seven of whom survived to adulthood. At the Museum of Natural History, one of the few precious surviving manuscript pages of “Origin of Species” has a colorful drawing on the back by one of Darwin’s boys, Francis.

The death of his eldest daughter, Annie, at age 10 devastated Darwin and apparently confirmed his rupture with religion. He never attended services again but would leave his family at the door of the church on Sundays.

Then he would walk home, his haven for four decades.

“My life goes on like clockwork,” Darwin wrote, “and I am fixed on the spot where I shall end it.”

True to his word, Darwin died at Down House on April 19, 1882.