Now, after scaling more than 20 mountain ranges in the sweltering desert sun, geologists have reassembled the crater into a semblance of its original shape. Evidence provided by pulverized rocks suggests the crater wide, as big as the Chesapeake Bay impact crater offshore Virginia. The findings, published Jan. 14 in the journal Geosphere, offer the most comprehensive view yet of the Alamo crater, the most accessible impact crater in North America.