The length and thickness of the penis is different for different people. The size of a soft penis (not erect) is much smaller than when it is erect. Some penises grow more when they get hard than other penises. In most cases, whether a penis is big or small, it can still be used for sex. It averages out to be around 3 to 6 inches long when not erect. The average size of an erect human penis is between 13 – 16 cm (5.1– 6 in). The average circumference of a penis is 12.3 cm (4.85 in) when fully erect. The penis grows bigger during puberty. At the start of puberty, the average length of the penis is . The penis reaches adult size about 5 years later. A study done in 1996 found the mean length of an adult man's penis is when it is not erect. The average length of an erect penis is about .
The foreskin is a fold of skin that covers the end of the penis. Cutting off the foreskin is called circumcision. The foreskin is connected to the head of the penis. During circumcision, the foreskin is removed from the penis. Circumcision is usually performed on infant males for medical, religious or cultural reasons. Circumcision is common in some parts of the world, such as the United States and the Middle East, but not common in some other parts of the world, such as Europe and China.
Some males have the foreskin cut off when they are adults because they have problems with their foreskin. Some males have the foreskin cut off because they want to change how their penis looks.
In common speech, you can say that someone is "cut" or "uncut", meaning circumcised or not circumcised .
In some religions, babies and young boys have their foreskin cut off. This is expected in Islam and Judaism. It is not required according to Christianity. In Judaism, infant males are required to have their foreskin removed as a sign of the covenant (ancient promise) made with God.
A young boy's penis skin is the same color as his other skin. Around age 12-15, a boy's penis skin gets slightly darker. This is normal because of puberty. This is caused by sex hormones (natural chemicals), especially testosterone. Testosterone makes more melanin. Melanin is the amino acid that causes skin color. (Sunlight also makes more melanin so skin gets a sun tan.)
Usually a teenager or man's penis side skin is slightly darker than other skin on his body. The tip (glans) of the penis is usually pink or red color even if the penis side skin is dark. If the man is not circumcised, the tip is usually covered by the foreskin. The foreskin is about the same color as the skin on the side of the penis.
If a man's penis skin changes color and he doesn't know why, he should go to a doctor. He could have an infection, diabetes or cancer. A sunburn on the penis can happen quickly. If a man is outside without clothes, he will get a sun tan. That is normal. Too much sun causes a sunburn. Doctors say to use sunscreen (sun cream) before and after nude swimming. A sunburn can happen in a few minutes on a very sunny day.
Since the oldest cultures the penis has assumed a strong importance as a symbol of fertility used also in religious ceremonies to propitiate the reproductive capacity of men and beasts. For example, in Roman paganism the god Priapus is characterized by a huge penis.
On the penis can be applied piercings and it can be tattooed as a body art form.
Sahara
The Sahara, in North Africa, is the largest desert in the world except for Antarctica. The Sahara is the largest hot desert.
It is bounded by the Atlantic Ocean, the Atlas Mountains, the Mediterranean Sea, the Red Sea, and the Sahel region. It runs through many countries including Morocco, Algeria, Tunisia, Libya, Egypt, Mauritania, Mali, Niger, Chad, and The Sudan. Most parts are uninhabited, but some people manage to survive in places where there is water.
The Sahara Desert is about 9,000,000 square kilometers (3.5 million square miles) in size. It has been both larger and smaller at different times. After the last ice age it became more fertile, then dried up again. It is the hottest place on the Earth, but not the driest. The driest is the Atacama Desert in South America. The Sahara has about the same size as the whole United States.
The Sahara has one of the world's most harsh climates. Typically, the Sahara landscape experiences little rainfall, powerful winds and wide temperature ranges. In some areas, there can be no rainfall for up to years at a time.
In the summer, daytime air temperatures across the Sahara often reach over 100 degrees Fahrenheit. In the winter, freezing temperatures may occur in the northern Sahara, and milder temperatures, across the southern Sahara. Snow may fall occasionally in some of the higher mountain ranges and rarely, on the desert floor.
The highest mountain is 3415 m, and is the "Emi Koussi" in Chad. Some mountain peaks in the Sahara Desert have snow even in the summer. The main mountain ranges is the Atlas Mountains in Algeria. The Sahara's lowest point lies in the Qattara Depression in Egypt, at about 130 metres below sea level. Sand sheets and dunes are about 25% of the Sahara. The other parts are mountains, steppes with a lot of stones, and oases.
Several rivers run through the Sahara. However, most of them come and go through the seasons, except for the Nile River and Niger River.
Metallic minerals are very important to most Saharan countries. Algeria and Mauritania have several major deposits of iron ore. There are also uranium mines, mostly in Niger. A lot of phosphates are in Morocco and Western Sahara. Petroleum is mainly found in Algeria, where it is very important to the economy. While mineral exploitation has led to economic growth in Sahara, this has rarely helped the indigenous population, as skilled workers have been brought from other countries.
Of the Sahara's around 4 million people, most live in Mauritania, Western Sahara, Algeria, Libya and Egypt. Dominant groups of people are Sahrawis and Tuareg people. The largest city is Nouakchott, Mauritania's capital. Other important cities are Tamanrasset in Algeria, and Sebha and Ghat in Libya.
Only 200,000 km² of the Sahara are fertile oases, where dates, corn, and fruits are grown. The few fertile regions today are fed by underground rivers and underground basins. Many of Sahara's oases rests in depressions (areas under sea level) allowing water to surface from underground reservoirs; artesian wells.
The soil in Sahara is low in organic matter. The soil in depressions is often saline.
Other sorts of vegetation include scattered concentrations of grasses, shrubs and trees in the highlands, as well as in the oases and along river beds. Some plants are well adjusted to the climate, allowing them to germinate within 3 days of rain and sow their seeds within 2 weeks after that.
Animals living in the Sahara include gerbil, jerboa, cape hare and desert hedgehog, barbary sheep, oryx, gazelle, deer, wild ass, baboon, hyena, jackal, sand fox, weasel and mongoose. The bird life counts more than 300 species. Reptiles, including 4 species of snake also live here. The most venomous scorpion in the world lives here.
4,000 years ago, the Sahara was a thriving savanna grassland with a great variety of wildlife. This included animals such as elephants and giraffes. Climate change has caused the rainfall to be less and turn the Sahara into the barren, desert wilderness as we know it today.
Paris
Paris (nicknamed the ""City of light"") is the capital city of France, and the largest city in France. The area is , and around 2.15 million people live there. If suburbs are counted, the population of the Paris area rises to 12 million people.
The Seine river runs through the oldest part of Paris, and divides it into two parts, known as the Left Bank and the Right Bank. It is surrounded by many forests.