A Thames Water borehole into the chalk aquifer under the North Downs, England at Albury. my picture, March 2009
<a href="https://en.wikipedia.org/wiki/User:SuzanneKn" class="extiw" title="wikipedia:User:SuzanneKn">SuzanneKn</a> at <a href="https://en.wikipedia.org/wiki/" class="extiw" title="wikipedia:">English Wikipedia</a>
29 March 2009 (original upload date)
<span class="int-own-work" lang="en">Own work</span>