Not built yet.
Although so far this has been a total failure for Trump, there are still a couple of more years left in his tenure. We'll see if he can deliver.
Why would you want a 1000 mile wall that would have a 1000 tunnels underneath it as soon as it was built?
I would suggest that you watch this entire 2-1/2 minute video until the end where it tells you they have found 240 tunnels in the San Diego region alone,and know there's more that they haven't found.
The ins and outs of U.S.-Mexico border tunnels - Los Angeles Times
Anything they can see, can and will always be compromised. Something they can't see won't even be attempted. Which is why high tech motion detectors, and more border patrol stations that can respond quickly to an alert is the only way to go.
And Democrats offered that up in lew of the Daca bill. That fell flat on it's face.
Then they offered 25 billion for Trump's POS wall, for an immigration bill that offered a path to citizenship and Trump turned that down flat.
So the REASON you don't have more border security today is because of TRUMP.
DACA offers Trump has rejected - CNNPolitics