If you're paying your dues on the Freedom Trail, you are tantalizingly close to a Zo's. There are two within a few blocks.

But they are easy to miss, with minimal signage, narrow storefronts, and just a few seats inside.

What you may notice: the line. Don't let that dissuade you: it moves quick.

What about the food?

Excellent!

Highly recommended:

• Original Gyros: authentic Greek rotisserie (100% lean pork) wrapped in a warm flatbread with tomato, onion, and tzatziki sauce (low-fat cucumber yogurt) - $9
• Spanakopita - Spinach Pie: spinach & feta cheese baked in a crispy, flaky filo dough (vegetarian) - $5

And here's how dedicated they are to speed: when you get to the cashier, that $5 spanakopita is exactly $5. Done. No extra change, taxes etc., to slow down the transaction. Hand her a fiver, and you're done, on the way out. 

Another indication of their dedication to speediness: this timelapse on their website. Can you feel the pride?

3 signs that Zo is a true lunch spot

1. There's the hole-in-the-wall quality. These places are tiny.
2. Then the speed, even though they aren't aggressive about it, like Al's around the corner.
3. Finally the hours: the two downtown places are open only between 11 am and 3 pm, M-F. 

Zo's also has trucks

Here's the weekly circuit: 

Monday: Dewey Square
Tuesday: High Street on the Greenway
Wednesday: Dewey Square
Thursday: Belvidere Street
Friday: Stuart Street

And, btw, here's how to pronounce "gyro"

With a very soft "g" according to the Chowhound crowd: close to "yee-roh," or "hee-roh."