Egypt (Arabic: مصر Miṣr), officially known as The Arab Republic of Egypt (Arabic: جمهورية مصر العربية Ǧumhūriyyat Miṣr al-ʿArabiyyah) is a republic in North Africa and Western Asia. The country is mostly desert, except for a thin strip along the Nile, plus a triangular bit (the Delta) where the Nile meets the sea. The Nile Valley/Delta is among the most densely-populated regions on the planet, and they light up like a Christmas tree—or perhaps Ramadan lamps—at night, so they are very, very visible from space. Egypt is traditionally divided into Upper Egypt and Lower Egypt, with Lower Egypt being the northern part of the country (i.e. the Delta), and Upper Egypt being the parts south. Where Upper Egypt meets Lower is Cairo, the nation's capital, and at 20 million-some inhabitants Africa's largest metropolitan area. The famous Pyramids are also there, and Memphis—the capital of the Old Kingdom—is not too far away, as is the old fort that served as the main Roman and Byzantine garrison for the province of Aegyptus/Aigyptos, proving that some places are just more strategic than others. Arabic is the official language and the language of the people, but the issue is kind of... complex. For that matter, its history and culture are also rather complex; see History of Modern Egypt for details.
Although Arabic is the major language of Egypt, the majority of Egyptians are not ethnically Arab according to the traditional definition; rather, your average Egyptian descends chiefly from the actual Ancient Egyptians, with at most a small number of ancestors hailing from the Arabian Peninsula. Whether or not Egyptians ought to be considered Arabs anyway is a point of contention. The Coptic Christian minority tends to identify more with Egypt's native ethnic group Copts seeing Arabization and Islam as hand-in-hand representations of foreign invaders (they still speak Arabic as a first language, of course, and Coptic only as a liturgical language). It should be noted though that the term "Copt" was first coined by the Arab invaders who didn't really have their own word for Egypt at that time. What they did was to take the Greek word Αἴγυπτος (Aigyptos) and then remove "Ai" which they wrongly assumed to be a redundant definite article, as well as what they correctly identified as an obligatory noun suffix "os", thus giving rise to the term "Gypt", which, due to the pecularities of the Arabic script and pronunciation would overtime be corrupted to the present-day "Copt". Thus, when we talk about "Coptic", what we actually mean is "Egyptian", and there are plenty of Coptic-DNA Muslims whose ancestors just never happened to intermarry with ethnic Arabs, yet in the eyes of society they're just as "Arab-Egyptian" as 90% of the population. All in all, while most modern Egyptians aren't exactly as closely related to their pyramid-building ancestors as, say, modern Greeks are related to the likes of Homer and Aristotle, a parallel with present-day Italians and ancient Romans would probably be quite fitting.
The Muslim majority is more divided. Some emphasize a common Arab identity, others prefer an Egyptian one, and still others prefer to identify with the Muslim Ummah (community of believers) as a whole. Many more, perhaps most, see no contradiction between the three. Anyhow, as in the rest of the predominantly Muslim world, religion is the most crucial aspect determining societal divisions, even if a sense of nationalism is much more deeply rooted in Egypt than it is in an overwhelming majority of other Muslim countries, maybe save for Turkey or Iran. Due to its commendable past, sheer size and the dominance of the Egypt-based media and entertainment (explaining the fact why Egyptian Arabic is widely understood all throughout the Middle East and Maghreb), Egypt has always been looked up to with respect and attention by its fellow Arab countries, even those much wealthier.note
However, Egypt, by dint of its large population (80 million out of ~200 million Arabic-speakers) and other factors, is widely considered to be the center of Arabic culture today: a very large proportion of Arabic movies, Soap Operas, music and literature come out of Egypt. In fact, the joke in Arab high culture is that Egypt writes, Lebanon publishes, and Iraq reads. The cultural impact of Egypt is—or at least was—great enough to deserve two articles: one on Egyptian Culture, and one on their biggest cultural export, Egyptian Movies.
Egypt is also a largely Muslim country (80% to 90%), and the native Coptic Christian church (a form of Oriental Orthodoxy) provides most of the rest (though the minority population has steadily shrunk since the Muslim Brotherhood took power). Despite what you might see in certain media, the numbers of Egyptians still worshiping Ra, Osiris and the others are not thought to be great. Those that do are probably more numerous outside of Egypt than within.
Egypt is still famous mostly as the home of the Pyramids, the Sphinx and lots and lots of temples, to say nothing of the Suez Canal.