All these years after soccer made a breakthrough in the United States, and I’m still not sure American fans appreciate the significance of the Uefa European Championship.

The World Cup is the planet’s biggest tournament.

The Euros are No. 2.

I suppose No. 3 would be the Copa America, which is going on in the U.S. at this moment. But the Copa is a significant distance behind the Euros, in terms of level of competition as well as level of global interest.

Why should that be?

–Because Europe has the world’s best professional leagues, and those clubs and their players have fans on every continent.

–Because Europe has many of the globe’s leading national teams. Spain, Germany, Italy, England, France, Portugal, the Netherlands, Belgium, Sweden, Denmark … Who wouldn’t want to see them play?

–Because the Euros do not overexpose themselves. Their tournament is held once every four years, the same years as the Summer Olympics (just ahead of them, actually), creating an excitement for when it rolls around again — as it has this year in France, starting tomorrow.

Meanwhile, the oldest continental tournament is South America’s Copa America, which goes back to 1916, but it has been held erratically over the past 40 years; it had an eight-year gap from 1967 to 1975, but it has been held in consecutive years several times, including last year and this year.

France is about as excited as France gets about a team event, which was made evident by the four-hour-plus grand oeverture concert the organizers put on for tens of thousands of fans on the Champ de Mars tonight, in the shadow of the Eiffel Tower.

France is worried about the potential for terrorism, and understandably so, but the first event went off without incident.

Meantime, this tournament is the biggest Euro Championship yet. It began as a four-team competition in 1960, expanded to eight in 1980, went up to 16 in 1996 and for the first time is at 24 teams, this year.

What started as a five-day event now runs 31 days, from June 10 to July 10, and helps give soccer junkies a summer fix by offering a high-caliber international match pretty much every day for a month, during a period when most of the world’s top players are taking time off.

By the mid-1990s I thought I followed soccer fairly closely, with the U.S. national team, and Concacaf and the World Cup, sometimes even the Copa.

But I was mostly oblivious of the second jewel in world football, a void I became aware of only after my arrival in Abu Dhabi in 2009, where “bigtime soccer” is by definition European soccer.

Uefa, the acronym for Europe’s governing body/confederation, is such a big deal here that some maintain its championship it is as important as the World Cup. At least on this side of the Atlantic.

A particular European vanity (one that has some merit, actually) holds that the World Cup is watered down by unworthy sides from North America, Asia and Africa, making the Euro competition more intense as well as competitive — most of the world’s top 30 teams are European, at any given moment.

(At the moment, they are 22 of the top 30 in the Fifa rankings.)

In the World Cup, no group has more than two European teams. In Euro championship, every team is a European team, for all that means in terms of hardened professionals playing at the highest level, in a fairly compact continent, where the average fan has extensive knowledge of all the best players, from Russia to Ireland, from Norway to Turkey.

So, here we are, the first 24-team tournament, which some have suggested makes the competition less intense. They note that nearly half of the 55 European national teams are in the tournament.

But to me it seems like it must be a pretty good tournament if the Dutch, the Danes, the Serbs and the Greeks couldn’t qualify for it.

Plus, 24 teams means two more groups and a round-of-16 knockout round — 51 matches overall, compared to 31 four years ago. More product, more chances to watch Euro national teams play in person or on TV.

Even in the U.S., where fans of international soccer ought to be interested.