When you arrive for the first time in a new city or a foreign country, the first thing you notice is the airport, and then the roads or the subway on the way to your hotel – the infrastructure.

Aside from making an impression on visitors, it’s the very foundation and backbone of a modern economy. Because it’s such a widespread, capital-intensive business, infrastructure presents a great opportunity for savvy investors.

More People = More Infrastructure

Infrastructure includes roads, bridges and tunnels, oil and gas projects, pipelines, cable networks, radio masts and satellites, airports and seaports, power plants, railways, subways, and water supply and treatment facilities.

As people have moved from rural areas to cities, the pressures on infrastructure have greatly intensified. In 1980, 39% of the world’s population lived in cities.

Now, more than half live in major cities, and this figure is expected to rise to 67% by 2050, according to a United Nations forecast.

To further put the pace of this growth into perspective, in 1979 there were only three cities in the world with a population over 10 million. In 2015, there are 23 cities with such populations, 18 of which are in emerging markets.

Asia is already home to seven of the world’s 10 largest megacities.

Amazingly, China has over 100 cities with a population exceeding one million, and every week, one million people are either born in or migrate to cities around the world.

Growth Poised to Explode

Along with this urbanization comes stronger economic growth and expanded international trade.

This means that unless these countries build more airports, roads, subways, power plants, railways, seaports, and pipelines, they will literally choke on their growth.

Morgan Stanley predicts that $22 trillion will be spent on these projects over the next decade. This includes communications infrastructure, such as mobile telecommunications and cable providers.

Here are some more interesting facts that highlight the global infrastructure challenge and investment opportunity.

• Mexico City’s population now exceeds 20 million.

• Only 5% of Brazil’s roads are paved.

• China is planning to build 97 new regional airports by 2020.

• 35% of Indian households don’t have access to electricity.

• About 50% of Jakarta’s 10 million citizens don’t have access to running water.

• South Africa is the world’s fourth-fastest mobile phone market in the world.

• About 83 % of the world’s population has access to clean water and just 58% have flushing toilets.

• The Royal Bank of Scotland estimates $1 trillion a year will be spent by emerging markets through 2030.

• The OECD expects the number of vehicles in emerging markets to double or even triple by 2030.

Follow the Sovereign Wealth Funds

The growing need for infrastructure and the steady investment returns it delivers have made it a favorite among sovereign wealth funds.

Sovereign wealth funds, with $7 trillion in assets, are putting roughly 25% of their investments in infrastructure projects around the world.

Because these huge projects are usually partnerships with host governments and often come with sovereign guarantees, these giant funds perceive that emerging country political and legal risks are significantly lower.

Infrastructure spending is also a favorite way to boost growth and generate jobs.

And with debt levels in many countries, including China, already high, everyone is looking for private and multilateral bank funding. The Wall Street Journal reports that about $45 billion worth of major Chinese construction projects are facing delays due to lack of funding.

The Asian Development Bank (ADB) in Manila allocates at least $10 billion each year to infrastructure. The soon-to-be launched China-led Asia Infrastructure Investment Bank (AIIB) will begin lending next year with $50 billion in capital and 57 founding members.

Even so, the World Bank estimates that there will be at least a $1 trillion -per-year gap in infrastructure funding.

I’m researching the best companies to play this deep and enduring growth trend, such as ABB Ltd. (ABB), Chicago Bridge & Iron Co. (CBI), and Caterpillar Inc. (CAT). Meanwhile, I suggest getting started with the Powershares Emerging Markets Infrastructure Portfolio ETF (PXR).

This basket includes companies based in America and Canada, plus 10% from France and Switzerland. The country weightings still tilt towards emerging countries, with China at 33%, Taiwan at 11%, and Thailand and South Africa both representing 6%.

So while the ETF is down 13.4% so far in 2015, it’s a balanced hybrid with a developed and emerging engine.

The sector breakdown is down the middle: 50% materials, 48% industrials, and 2% utilities. The materials sector includes a fair amount of mining stocks and material companies such as Taiwan Cement.

Get going right now on this unstoppable trend.