ByIan Casey,Fiona Trott,BBC News
The father of missing British teenager Jay Slater says he is experiencing "a living hell", as the search for his son in Tenerife enters a second week.
Warren Slater said "I just want him found", while speaking to reporters in the town of Santiago del Teide, around four miles (6.4km) from where search teams are looking.
On Monday, police cars parked at the entrance to a mountain track near where the 19-year-old's mobile phone was last traced.
Mr Slater has not been heard from since calling one of the friends on the island with him eight days ago - telling her he was lost, his phone was running out of battery and he needed water.
Specialist dog teams have also been out looking for him, with much of the search focusing on an area near a national park in north-western Tenerife.
Mr Slater's father has been appealing for help from the local community in Santiago del Teide, where the family went after an unconfirmed report of a possible local sighting.
They have put up missing posters written in Spanish, including at the tourist information centre and in shop windows.
Warren Slater was emotional as he told reporters: "Somebody must know something. I just want him to be found. End of.”
The search teams are working in challenging conditions at Rural de Teno National Park - Mr Slater's last known location.
Officers from the Guardia Civil in the Canary island were spotted searching two structures at the bottom of a ravine in the park on Sunday.
Efforts appeared to be primarily focused on the one area after days of searches in the nearby village of Masca and the surrounding landscape.
When asked how the search operation is going, police in Tenerife said that they do not comment on ongoing investigations.
One man who had flown out from the UK to help described his role in the search operation through ravines as like "looking for a needle in a haystack".
Mountaineer Paul Arnott, 29, of Flitwick, Bedfordshire, said: "You cannot believe how steep and big an area it is until you get out here.
"I thought there would be more people searching, though."
Mr Slater's friends and family have said he had earlier left the group he travelled with in the tourist hotspot of Playa de las Americas, on the south of the island.
After leaving the NRG music festival at Papagayo night club, the apprentice bricklayer got in a car with two men he had met to drive to the national park in north-west Tenerife.
In a statement, NRG described Mr Slater's disappearance as a "devastating situation" that "has deeply affected us all". Organisers continued to "hope for his safe return," it added.
Lancashire Police said last week it had offered to assist Spanish police searching for him, but were told their counterparts in Tenerife felt they had enough resources.
Mr Slater was on his first holiday without family and had travelled to attend the festival with two friends.
One of them, Lucy Law, is thought to have been the last person to speak to him, said he told her over the phone he had missed a bus and decided to walk the 10-hour journey home but was lost, needed water and only had 1% battery left.
Earlier in the week a fundraising page set up by Ms Law to help find him gathered more than £30,000 worth of donations.
Mr Slater's employer, PH Build Group, said it had deleted a post about the missing teenager on its Facebook page after it was inundated with "negative comments."
"Jay has been with us since he left school and is liked by all. He's a valued member of our team and we stand by him," the construction company wrote.
"The fact is he's a 19-year-old lad missing in a foreign country. He needs to be back home where he belongs."
The Rural de Teno Park is about a 40-minute drive from where Mr Slater and his friends were staying.
A remote and wild national park, it is a world away from Los Cristianos and Playa de las Americas, the party town holiday resorts of the island’s south coast.
Deep ravines and huge daunting mountains make the national park a difficult place for the Spanish search teams to navigate.
- Sunday 16 June - Jay Slater and friends attend final day of the NRG music festival at Papagayo night club in the tourist hotspot of Playa de las Americas
- Monday 17 June - Between 03:00 and 06:00 BST Mr Slater got into a car with two men he had met during the holiday and left Playa de las Americas
- 07:30 - Mr Slater posts a photograph on his Snapchat account showing him at the doorway of a property, tagged with the location Parque Rural de Teno
- Between 08:30 and 09:00 - Mr Slater calls his friend and says he missed a bus back south and was attempting to walk the 10-hour journey
- The call cuts out, with his phone's last location showing a path in the mountainous Rural de Teno national park, popular with hikers
- Tuesday 18 June - Despite his friends searching the area, no sign of Mr Slater emerges and he does not return to his accommodation
- Local police and mountain rescue teams begin searching and his mother and brother board a flight to Tenerife
- Wednesday 19 June - The Spanish Guardia Civil continue the search using drones, dogs and a helicopter but no trace is found
- The search is briefly moved to the Los Cristianos area in the south of the island due to a potential sighting, but police quickly "discount" that lead and move the search back to the original area
- Thursday 20 June - The Guardia Civil, mountain rescue, firefighters and volunteers return to scour the national park
- Friday 21 June - Lancashire Police confirms it has offered to help the search but says Spanish Police are "satisfied that they have the resources they need"
- Saturday 22 June - Police, rescue dog teams and firefighters continue combing the mountainous terrain at Rural de Teno
- His mother, Debbie Duncan, issues a direct plea to her son, saying: "We just need you home"
- Sunday 23 June - Police examine outbuildings at the bottom of a ravine in Rural de Teno, close to where his phone last pinged
