I apologize for the length as I could not make it any shorter.
Rev 13 speaks of a beast rising out of the sea and another beast rising out of the earth. The beast rises up out of the sea as the sea here is symbolic of people and nations as in a sea of humanity, Daniel Chapter 7:1-8; Revelation 17:15. This beast is a political, economic and religious power that works through the beast that rises from the earth, Daniel 7:24,25. This beast out of the earth is a consolidated religious power where the son of perdition will lead a great falling away from truth before the return of Christ, 2Thessalonians 2:1-4, as he sits on the side of the north in Jerusalem, Isaiah 14:12-15.
Because of the ToS I can not get into a deeper explanation, but can give you some scriptures to study about who the ten nations, four nations are in Daniel chapter 7 and 9 as this gives light to the two beast in Rev 13.
Daniel Chapter 7 was an interpretation of a dream that Nebuchadnezzar had about four nations. Within these four nations we see how Satan tries to rule through man, but the kingdom of God prevails in judgment against these nations and the nations are turned over to the people of God for eternity. Notice also where these present day places in parentheses are located. Pagan nations also were often called beast in the Old Testament, which shows us to not take some words literally as many are also symbolic for our spiritual understanding.
Four nations:
Babylonian Empire:
(Iraq) The lion represents the winged lions that guarded the royal places of Babylon.
Medo – Persian Empire:
(Iran) The ribs of the bear are part of the consuming greed that devours the first empire.
Grecian Empire:
(Greece, Turkey, Syria, Egypt) Four wings of the leopard described the swiftness of this empire that ran from 334-331BC. It wrestled world dominion from Medo-Persia. After the death of Alexander the Great the kingdom was divided into four minor kingdoms that continued as prominent factors in world politics until the Roman Empire gathered it back as one kingdom.
Roman Empire:
Iron represents the stronghold this nation had. Daniel chapter 2 mentions the iron element of this empire that it to will be divided and broken as God will set up a kingdom that will never be destroyed.
Daniel 9:24-27 the Vision of the Seventy Weeks
Vs. 24 this verse shows us that the timing from Ezra to the cross was 490 years as within that time Ezra was reestablishing the law in Jerusalem until Jesus had fulfilled the end of transgression, made an end to sin, made reconciliation for iniquity and bring everlasting righteousness and to seal up the prophecy to make an end to the law through the cross.
Vs. 25 from the time of the cross, which also means the last days, which includes what some like to separate and call “The Great Tribulation”, which is not mentioned anywhere in scripture and is not a separate event after the elect of God are caught up, but as the last days so we are in tribulation times until the end of the world as we know it, Acts 2:17; Hebrews 1:1,2; Matthew 24:4-31; Mark 13:24-31; Luke 21:5-36. These are just some of the scriptures that support that we will go through all things of Rev Chapter 6-21. Everyone will have opportunity to come unto salvation through Jesus Christ if they would only believe until the door of salvation is closed when Jesus calls us and we meet him in the clouds, which after this time no one can be saved, Matthew 25:10.
Vs.26 after 434 years that end in the year AD29 shall Messiah be cut off. Jesus was crucified after he was baptized in AD 29 three and a half years later. Jesus was cut off (killed) by the people of the prince, which means National Israel or other words the Pharisees, Sanhedrin and the high priest that destroy the city and the sanctuary (meaning Christ) and the end thereof shall be with a flood (Gods wrath) that will put an end to abominations by desolation or in other words a ruin to evil deeds. Daniel 9:27 explains the definitions of desolation of abominations or the ruin of evil deeds. There is no actual Desolation's of Abominations where the so-called Antichrist will take a literal throne, but the desolation will be when the Pope tries to take his throne in Jerusalem, Daniel 11:36-45. Gods’ word never defines one great Antichrist, but says there are many antichrists, 1John2:18; 11 Thessalonians 2:1-12; Revelation 11:7. The seven years that some call the seven year tribulation means three and a half years of Jesus teaching before he was crucified and three and a half years of Steven teaching before he was stoned to death, which took place after Jesus was ascended.
Vs.27 the 70th seven began with Christ baptism in AD 29 and three years later at the end of the first half of the 70th seven sacrifices and offering ceased because Christ hung on the cross. From the giving of the law in 458BC when Ezra went to establish the law, or to rebuild the spiritual city right to the cross where the first 69 sevens. The 70th seven is from the time of the cross until Jesus comes back in the air to call his Bride home and for the overspreading of abominations he will make desolate, or make an end to all who would not believe.