Madrid - This year's Tour of Spain will start in Pamplona on August 18 with a team time trial and the winner unveiled in Madrid on September 9 after a string of demanding stages including six that finish at altitude.
One of those climbs is the dreaded Cuitu Negru in the northern Asturias province, graded in parts at 20%.
The opening time trial in Pamplona will be along the streets the Basque city uses to run bulls for its famed San Fermin festival in July.
Spanish rider Juan Jose Cobo, shock winner of the 2011 Vuelta, described this year's edition as "extremely demanding."
"Maybe too demanding for me," the 30-year-old Movistar rider told AFP, picking out the block of three stages in Asturias that all finish at altitude.
"The three Asturias stages will be decisive for this Vuelta," he said.
"I've planned a relatively light first half of the season to remain fresh for the Tour de France and be able to last through to the Vuelta."
Euskatel rider Samuel Sanchez highlighted the 16th stage climb of Cuitu Negru as the most testing.
"Of course, there's also Bola del Mundo one day from the arrival in Madrid, but the Cuitu Negru climb can change a lot of things.
"As a whole, this Vuelta offers up an interesting course. There are lots of summit arrivals but they are short and not never-ending.
"The individual time trial is quite short (40km) and shouldn't have a great bearing on this race," the 33-year-old Asturias native said.
Race director Javier Guillen said of the 67th edition of the Tour of Spain: "We wanted to draw up an explosive course.
Serious racing will start at the end of the first week, with a first mountain climb to the Valdezcaray ski resort on the fourth stage before the riders tackle the Gallina Col in Andorra four stages later.
After an air transfer to Galicia in the northwest, the peloton face the individual time trial in the 11th stage before heading up into the northern mountains.
The 20th stage sees riders climb the Bola del Mundo before descending towards the Spanish capital.