Teams of German and Portuguese cops, as well as firefighters, face the daunting task of hunting for clues 18 years on from the disappearance of the British three-year-old in 2007.
Portuguese and German police launched joint searches of an area in the Algarve, a short distance from the resort of Praia da Luz where the British toddler disappeared.
LIVE UPDATES: Follow MailOnline's live coverage as police resume searches for Madeleine McCann in the Portuguese resort Praia da Luz where she vanished from 18 years ago during a family break.
Convicted paedophile Christian Brueckner , 48, is the man German investigators believe abducted Madeleine from her family's rented holiday apartment in Portugal in 2007.
A well-placed Portuguese source confirmed this week's operation was scheduled get underway tomorrow but said some preparation work may take place beforehand
The university chemical engineering student, who started swimming competitively at age eight, is also predicted to compete for Gerry's native Scotland at the 2026 Commonwealth Games.
May is an especially heart-wrenching month for Kate and Gerry McCann, as last Saturday marked 18 years since their daughter, Madeleine, disappeared from her bed in a holiday Portuguese resort.