They are Slavs, they speak a Slavic language – Czech, which is almost the same as Slovak and similar to Polish. But Czech was not always the official language in the Czech Republic, until 1918 the country was part of the Austro-Hungarian Empire, formerly the Habsburg Monarchy, where German was spoken, there were also many Germans living in the Czech Republic, they were forced to leave after WWII. Today, the Czech Republic is a more or less homogeneous state in terms of ethnicity, with only small communities of Poles, Ukrainians and Roma.
The culture is mainly Christian and predominantly Catholic, although today most of the population considers themselves atheists, everyone still celebrates Christian Christmas and Easter, and there are many smaller and larger churches in the country. Czechs are specific in their love for mountains, although there are rather smaller mountains in the territory (the highest mountain Snězka is 1602 m above sea level), everyone is a tourist here, which is why there are the best tourist signs in the world. Many Czechs like to ski and generally love the mountains.
As for history, since 1918 Czechoslovakia became a republic, despite a brief split during World War II, it remained with Slovakia through the entire communist era until 1991 when the two states separated and today there is a Czech Republic and another state, the Slovak Republic. The Czech Republic was part of the Eastern bloc of the Soviet Union until 1989 when the Velvet Revolution took place, of which the Czechs are very proud, and its anniversary is celebrated every year on 17 November. In the 1990s the country experienced turbulent years of economic growth but also of corruption and partial lawlessness, but in the new millennium the situation has calmed down and the country is now developed and one of the most secure in the world.