Fun facts about The Joshua Tree, the 1987 U2 album whose 30th anniversary is being celebrated with a tour that arrives at Lincoln Financial Field on Sunday:

– The photo on the front cover of the Irish band's fifth album, by Anton Corbijn, was not taken anywhere near Joshua Tree, Calif., but 200 miles north at Zabriskie Point in Death Valley.

On the gatefold spread of the original LP, the super-serious band posed in front of a lone Joshua tree — official name Yucca brevifolia, of the agave family — that looks like it's trying to throw its arms around the world, to paraphrase a song from the band's next (even better) studio album, 1991's Achtung Baby. The tree has not aged as well as the music; it died in 2000.

– Before their most majestic album came out, U2 were already an arena attraction, but The Joshua Tree made them stadium-size. In Philadelphia, they played the Spectrum in September 1987 and came back to the much larger JFK Stadium less than two weeks later.

Bono performed the latter show with his left arm in a sling, after dislocating his shoulder in Washington. For the JFK encore, Bruce Springsteen joined him for a duet on Ben E. King's "Stand By Me."

– The archetypal U2 album, which was produced by Brian Eno and Daniel Lanois, is their biggest seller, moving more than 20 million copies. But it was nearly not called The Joshua Tree. Its working title reflected the Dubliners' then-and-now fixation on the country that they set out to conquer like so many musical invaders before them: Two Americas.

What's that you say? Is Bono such a far-seeing rock prophet that, way back during Ronald Reagan's presidency, he predicted the my-way-is-the-only-way deep divisions that separate left and right in Donald Trump's America?

Well, not exactly. The Two Americas idea wasn't so much about liberals and conservatives being at each other's throats, or the red-and-blue-state cultural divide then taking shape. It was about, as Bono put it in a National Public Radio interview this year, "the mythic America and the real America. … America's sort of a promised land for Irish people — and then a sort of potentially broken-promised land."

The Joshua Tree has a well-deserved reputation as a grand statement about the United States.

The magisterial, sweeping sound is as vast as the desert sky on the remarkable one-two-three punch of opening tracks "Where the Streets Have No Name," "I Still Haven't Found What I'm Looking For," and "With or Without You." Music critic Ken Tucker called the latter "the first Top 10 hit ever to invoke the crucifixion as a metaphor for a bummed-out romance" in his Inquirer review.

The band's signature sonics are in place — the helicopter swirl of the Edge's guitar in lockstep with the rhythm section of bassist Adam Clayton and drummer Larry Mullen Jr., overlaid with Bono's soaring, incantatory vocals. Americanisms are employed to convey authenticity — harmonica swagger on "Trip Through Your Wires," slide guitar on "Running to Stand Still."

U2 had obsessed about the U.S. before. Their rise coincides with the Reagan years, with their debut album, Boy, preceding the 1980 election by a month. (In December that year, the band played its first Philadelphia show, at the Bijou Cafe on Lombard Street.) 1984's The Unforgettable Fire included not one but two songs about the Rev. Dr. Martin Luther King Jr., including the immortal "Pride (In the Name of Love)," not to mention "Elvis Presley and America."

But on Joshua Tree, particularly the searing "Bullet the Blue Sky," along with critiquing U.S. foreign policy, the band addressed the strain of intolerance that runs throughout America's bloody racial history in ways that seem all too familiar today.

"You plant a demon seed, you raise a flower of fire," Bono sings, invoking a biblical struggle in which the forces of darkness appear to be winning. "See them burning crosses, see the flames higher and higher." The song includes a dreamlike sequence inspired by a trip Bono took to Central America in the latter stages of the cold war. It ends with violence-fleeing refugees "who run into the arms of America."

U2 have never entirely let go of their fixation — even Achtung Baby, the Berlin- and Dublin-made 1991 masterpiece that did its best to explode the band's holier-than-thou earnestness, took cues from 24/7 American media immersion.

And when Bono, who has called the Declaration of Independence "the liner notes of America," came to Philadelphia in 2007 to receive the Liberty Medal for his AIDS- and poverty-fighting efforts, he told me, "What I love about America started in Philadelphia. It's the expression of those values that the world needs to see."

In that interview, the 57-year-old frontman born Paul Hewson also said that for U2, "There's enormous pressure to be relevant. Which is different than successful, and a lot harder."

That's where Donald Trump comes in.

U2 have had an amazing run of not giving in to nostalgia. But the band's most recent truly terrific album was 2000's All That You Can't Leave Behind. And the group with the messianic leader in tinted glasses let their hubris — and compulsion to connect with a mass audience — get the best of them with the release of 2014's William Blake-inspired Songs of Innocence.

Thanks to a business deal with the largest corporation in the world, that album was available for free download in the iTunes players of 500 million Apple customers. Many took offense at having music forced on them — "Who is U2?" some tweeters wondered — and a public relations disaster ensued. The band has seemed at a loss since, as the followup album, Songs of Experience, has yet to materialize.

But after a campaign in which candidate Trump fired up followers with promises to build a "big, beautiful wall" along the U.S.-Mexican border, an album that at once celebrates America as a land of hopes and dreams and raises its voice in opposition to forces of intolerance … well, it's quite handy to have one of those in your back pocket, ready to celebrate its 30th anniversary.

Waiting till after Trump's election, the band announced the Joshua Tree 2017 tour in January. It allows them to potentially experience the best of both worlds: Speaking to the moment while bringing the whole of their fan base back into the fold by playing the cherished album in its entirety.

And, yes, that means fans will finally get to hear the never previously performed "Red Hill Mining Town," a standout song on an album full of really good ones you might have forgotten, such as "One Tree Hill," and "In God's Country."

"Things have come full circle," the Edge (born David Evans) said when the tour was announced. "That record was written in the mid-'80s, in the Reagan-Thatcher era of British and U.S. politics. It was a period when there was a lot of unrest."

The Joshua Tree acknowledged those conflicts, but being an ultimately heroic U2 album, it also rang out with hope in troubled times.

"It feels like we're right back there in a way," the Edge said. "It just felt like, 'Wow, these songs have a new meaning and new resonance today.' "

Do they? That'll be put to the test on Sunday at the Linc.

U2 with the Lumineers.

7 p.m. Sunday at Lincoln Financial Field, 1 Lincoln Financial Field Way.  Sold out.   267-570- 4000.