Question:

Are the twelve Jordan crossing stones still visible today at Gigal?

Answer:

"And the children of Israel did so, just as Joshua commanded, and took up twelve stones from the midst of the Jordan, as the LORD had spoken to Joshua, according to the number of the tribes of the children of Israel, and carried them over with them to the place where they lodged, and laid them down there" (Joshua 4:8).

You must remember that this event happened about 3,500 years ago. Few things last that long, let alone a stack of twelve large stones. No pile of stones have been found and identified, it is very likely will not be found.