Just how many is 2 million Syrian refugees?

The number of Syrian refugees topped 2 million this week, according to the United Nations human rights agency, UNHCR.

“The war is now well into its third year and Syria is hemorrhaging women, children and men who cross borders often with little more than the clothes on their backs,” the UN report, released on Sep. 3, said.

Now, we know 2 million is a lot. But at the same time, it's a hard number to picture. 

For example, there are 2 million people in this photograph of Barack Obama's inauguration in 2009. You can't even see them:

(Jewel Samad/AFP/Getty Images)

So, just how many is 2 million? Here are some numbers to give you context:

1) THE POPULATION OF LATVIA

(Ilmars Znotins/AFP/Getty Images)

2) MORE THAN TWICE THE POPULATION OF SAN FRANCISCO

(Justin Sullivan/Getty Images)

3) THE NUMBER OF IRAQIS WHO HAVE FLED THE COUNTRY SINCE 2003

(US Dept. of Defense/Wiki Commons)

4) FIVE TIMES THE NUMBER OF PEOPLE DISPLACED BY HURRICANE KATRINA

(Carlos Barria/AFP/Getty Images)

5) FIVE TIMES THE NUMBER OF PEOPLE WHO ATTENDED WOODSTOCK

(Courtesy Wiki Commons)

6) 13 TIMES THE NUMBER OF TIBETANS LIVING IN EXILE

(Prakash Mathema/AFP/Getty Images)

7) TWICE THE NUMBER OF PEOPLE WHO GATHERED FOR POPE JOHN PAUL'S BEATIFICATION 

(Alberto Pizzoli/AFP/Getty Images)

8) HALF THE NUMBER OF PEOPLE WHO ATTENDED A ROD STEWART CONCERT IN RIO IN 1996

(Julio Cesar Aguilar/AFP/GettyImages)

9) THE POPULATION OF HOUSTON, TEXAS

(Scott Halleran/Getty Images)