The USA invented the Global Positioning System (GPS) in the 1970s. (21) , it was a military project, but now anyone can use the system to find out exactly their locations and track their movements. For GPS to (22) , your receiver (or smartphone) must be in contact with four or more satellites in space. Then it uses the data to calculate the (23) time and position on Earth. However, it is not enough for survival situations (escaping the jungles or deserts) because you (24) know your direction (which way you are moving) and your speed (how fast you are moving). GPS provides this information, by tracking your position over time. For modern explorers, a smartphone and GPS are (25) as a compass, torch and map. With the right applications, your smartphone will help you survive.

One of Mexico's traditions is called the Quinceañera, which means 'fifteen-year-old'. It is when a young girl turns 15 and she has a big party to celebrate. In 16th-century, a girl turning 15 meant she had to decide between giving her life to God or getting married. The girl would wear a white dress; however, girls now wear dresses of any colour. The party costs a lot of money.

At the birthday party, there’s music, dancing and lots of food. Family and friends are invited to enjoy the special day. The father dances with his daughter and there is a more modern dance by the birthday girl. The Quinceañera looks like great fun. The age 15 has so much more significance in Mexico than in England. Mexican culture is really interesting. There is so much more to learn about!