“To me the local component is really important — businesses that have not been completely taken over by Gap and Starbucks. I think there is a real sense of community. It feels safe because people watch out for each other.

“The block feels vibrant from morning until night. You can be there at midnight as well as 10 o’clock in the morning and feel safe. And small kids feel comfortable there.

“I wouldn’t want to say there is a formula. Each block is different. All the buildings are not the same. A great block might have a uniqueness to it, but enough of all the other characteristics to make it lively.

“I don’t think that a great block necessarily excludes the car, but it’s a great place to walk.“And a great block, of course, has people living over the store.’’

Here are some other things to look for, Frey said:

• Continuous buildings, with no more than one narrow parking lot or vacant lot, garage entrance or loading bay to interrupt the flow.

• A mix of uses in the buildings, particularly on the ground floor but on upper floors as well, with various shops, offices, restaurants and/or residences. Hint: a convenient mix of uses is most likely found on a block with many separate, small, adaptable buildings, rather than one or two large, single-use buildings.

• Sidewalks wide enough for multiple human activities, such as walking and dining. Bonus: public transportation stop, bike lane, car sharing-space or other non-car transportation facility.

• Trees, canopies, or other sun and rain protection plus a sprinkling of intangibles like beauty, architectural style, sense of place, culture.

If all that sounds like a lot, it is. A great block packs a lot into a compact area.

Don’t be discouraged. That doesn’t mean that South Florida’s best block must have all those elements. But it should have at least some.

After all, Davis said, there are many great blocks in cities across the country — from Berkeley, San Diego and Portland on the west coast to Brooklyn in the Northeast — that may not be spectacular, or iconic, or even look that great in a photograph, but possess those special urban qualities and energy that many Americans are now hunting for.

“People are starting to understand what this is really about,’’ he said. “I think these ideas are really very much in the public consciousness now.’’

Good block-hunting.