Azerbaijan gained state independence twice in the 20th century. The life of the Azerbaijan Democratic Republic, which existed in 1918-1920, lasted only 23 months. In Azerbaijan, which regained its independence in 1991, it was not easy to preserve it.
                 
In the second half of the 1980s, a pre-crisis situation arose in the economic, political and spiritual life of the Soviet empire. The dogmatic communist ideology, which was the moral support of the current system of government, had collapsed. In the union republics, signs of national self-awareness, protests against the trampling on human rights and looting of the country’s wealth were growing stronger. The collapse of the USSR was also conditioned by important external factors.

To weaken the centrifugal force, Moscow made more extensive use of the traditional "divide and rule" policy, inciting national conflicts and inciting bloody divisions among peoples. The Kremlin has inflamed the so-called "Nagorno-Karabakh problem" in order to keep the significant geopolitical territory of Azerbaijan and the entire South Caucasus under its control. Western nations, which saw national conflicts as an important means of destroying the Soviet empire, also took an active part.
 
The first open rally of the organization called the "Karabakh Committee" was held in Yerevan in October 1987. Official Moscow did not hesitate to express its positive attitude towards the Karabakh movement to the world through the speech of Abel Aganbekyan, Mikhail Gorbachev's adviser in Paris, in November 1987. The "Miasum" (unification) movement for unification with Armenia was expanding among the Armenians of Nagorno-Karabakh.

From the beginning of 1988, Armenian separatists started to stage continuous mass rallies and demonstrations in Khankendi. The first victims of the enmity between the two nations were again the Azerbaijanis living in their homeland in Armenia.

The cold-blooded reaction of the Soviet leadership to the crimes committed against Azerbaijanis in Armenia further unclasped the hands of the Nagorno-Karabakh separatists. Moscow urged the Armenians, who want to separate the legal territory of Azerbaijan from it and unite it with Armenia, to stand up for so-called “their lands” and constitutional rights.

The patience of the Azerbaijani people was running out. The wave of protests was growing day by day. The highest period of the spontaneous phase of the people's movement began on November 17, 1988. The people realized that the Moscow-appointed leaders of the republic were not protecting their interests. Only a leader brought to power by the people could defend the interests of the people. 
 
The Presidium of the Supreme Council of the USSR grossly violated the rights of the Azerbaijani people and adopted a decision "On the introduction of a special form of governance in the Nagorno-Karabakh Autonomous Oblast of Azerbaijan SSR" on January 12, 1989. By the decree of the USSR Council of Ministers dated May 6, 1989, the administrations and enterprises of the NKAO were removed from the subordination of the Azerbaijan SSR. 
                       
An extraordinary session of the Supreme Council of the Azerbaijan SSR was convened on September 15. The session adopted resolutions on the wider discussion of the draft laws on the abolition of the Nagorno-Karabakh Autonomous Oblast, the amendments to the Constitution of the Azerbaijan SSR, stipulating that the borders of the republic could be changed only through a national referendum. The extraordinary session of the Supreme Soviet, held on September 23, 1989, adopted the Constitutional Law "On the Sovereignty of the Azerbaijan SSR". This law lifted the spirit of independence and victory among the people.
 
On June 16, 1989, the founding conference of the Popular Front of Azerbaijan was held in Baku. The Program and Charter of the Front were approved at the conference. 
 
On December 31, unrest broke out at 137 km of the Soviet Union-Iran border along the Araz River. The border facilities were destroyed. Those who gathered at the border on both sides crossed the Araz River and met each other. On January 18, border facilities in Bilasuvar and Jalilabad regions were destroyed. The Azerbaijanis met their blood brothers from the south. 
 
On January 15, 1990, the Presidium of the USSR Supreme Council declared a state of emergency in NKAO and adjacent regions. On January 19, 1990, the Presidium of the USSR Supreme Soviet, without the consent of the Supreme Council of Azerbaijan, issued a decree "On imposing a state of emergency in the city of Baku" from midnight on January 20.

150 people were killed and 744 injured in Baku and the regions of the republic during the attack of the Soviet army on Baku and other residential settlements of the republic. Martyrs who sacrificed their lives on January 19-20, 1990, were buried in the highest part of the city - Mountain Park.

Immediately after the tragedy, on January 21, 1990, national leader Heydar Aliyev visited the office of Azerbaijan`s permanent representation in Moscow. He expressed solidarity with his people, sharply condemned the Soviet leadership for committing the bloody tragedy and exposed those who violated the law, democracy and humanity.

Having realized the importance of being with his people in this responsible and difficult but honorable period of history, Heydar Aliyev arrived in Baku on July 20, 1990. He was not allowed to stay in Baku, so he left for his native Nakhchivan. Heydar Aliyev was elected deputy to the Supreme Soviets of Azerbaijan SSR and Nakhchivan ASSR. He guided the people's struggle for freedom with his wise and far-sighted policy. On November 17, 1990, the session of the Nakhchivan parliament chaired by Heydar Aliyev approved the historical resolutions on erasing the words "Soviet Socialist" from the name of the Autonomous Republic, while the tricolour of the Azerbaijan Democratic Republic was adopted as a state flag, to which effect a legislative initiative was motioned in the Parliament of Azerbaijan.
 
The name of the state was changed to "Republic of Azerbaijan" at the session of the Supreme Council of the Azerbaijan SSR on February 5, 1991. The flag of the Democratic Republic of Azerbaijan was approved as the state flag.
      
On August 30, 1991, the extraordinary session of the Supreme Council of the Republic of Azerbaijan, convened at the request of the people, adopted the "Declaration on the restoration of state independence of the Republic of Azerbaijan". A new era has begun in the history of the Azerbaijani people.
  
The session of the Supreme Council of the Republic of Azerbaijan dated October 18, 1991, unanimously adopted the Constitutional Act "On the State Independence of the Republic of Azerbaijan". The Constitutional Act consists of 6 chapters and 32 articles.

A national referendum was held in the Republic of Azerbaijan on December 29. More than 95 percent of those eligible to vote participated in the referendum. The Azerbaijani people unanimously supported the state independence of the republic.
 
The foreign countries recognized the independence of the Republic of Azerbaijan. On March 2, 1992, the Republic of Azerbaijan was admitted to the UN membership and joined many important international conventions and pacts approved by this organization.

In May 1992, the Milli Majlis (National Council) approved the National Anthem of the Republic of Azerbaijan (music by Uzeyir Hajibeyov, lyrics by Ahmad Javad), and soon after, the National Emblem with a tricolor flag and an eight-pointed star with an image of the flame inside it.

Having restored its independence by the will of the people, the Republic of Azerbaijan lived through a turbulent period in 1991-1994 and faced the threat of losing its state independence. Thanks to the sound policy implemented by the national leader Heydar Aliyev, all difficulties were overcome, and today Azerbaijan occupies its rightful place among the nations of the world.

According to the "Law of the Republic of Azerbaijan on Independence Day" dated October 15, 2021, October 18 was declared the Day of Restoration of Independence. Independence Day is celebrated annually in Azerbaijan.

Recommended literature:

1. Qaffarov, Tahir Baqi oğlu. Azərbaycan tarixi : XX əsrin 80-90-ci illəri / T. B. Qaffarov ; elmi red. T. T. Mustafazadə. - Bakı : Mütərcim, 1997. - 141 s.
2. Heydər Əliyevin neft strategiyası: Azərbaycanın müstəqilliyi və rifahı naminə [Mətn] : [2 hissədə] /Azərbaycan Respublikası Prezidentinin Katibliyi. - Bakı: 2001. - 478 s.
3. Haqverdiyev, Musa Bədirxan oğlu. Müasir dövrdə ümumavropa təhlükəsizliyi və Azərbaycan: monoqrafiya : Azərbaycan Respublikasının Dövlət müstəqilliyinin 20 illiyinə və Avropa Şurasına qəbulunun 10 illiyinə həsr olunur /M. B. Haqverdiyev ; elmi red. A. N. Abbasbəyli. - Bakı: Elm və təhsil, 2011. - 229 s.
4. Azərbaycan Respublikasının xarici siyasətinin əsas istiqamətləri: 1991-2016: [məqalələr toplusu] / F. Məmmədov [et al.]; red.: F. Məmmədov, C. Vəliyev, A. Məmmədov; Azərbaycan Respublikasının Prezidenti yanında Strateji Araşdırmalar Mərkəzi.- Bakı: Poliart MMC, 2017.- 904 s.
5. Azərbaycan Respublikasının tarixi: 1991-2003 / AMEA A.A. Bakıxanov adına Tarix İnstitutu; layihənin rəh., elmi red. Y. M. Mahmudov, red. heyəti: A. A. Əlizadə [et al.] I cild: Heydər Əliyev dövrü.- Bakı: Azərbaycan Tarixçiləri İctimai Birliyi, 2016.- 704 s.
6. Azərbaycan Respublikasının tarixi: 2003-2016 / AMEA A.A. Bakıxanov adına Tarix İnstitutu; layihənin rəh., elmi red. Y. M. Mahmudov, red. heyəti: A. A. Əlizadə [et al.] II cild: İlham Əliyev dövrü.- Bakı: Azərbaycan Tarixçiləri İctimai Birliyi, 2016.- 716 s.
7. Müstəqil Azərbaycanın 25 ili səfirlərin gözü ilə: məqalələr toplusu / Azərbaycan Respublikasının Prezidenti yanında Strateji Araşdırmalar Mərkəzi, Azərbaycan Respublikası Prezidenti Administrasiyasının Xarici əlaqələr şöbəsi; ideya müəl. N. X. Məmmədov.- Bakı: Best-TMS MMC, 2016.- 645 s.
8. Qasımov, Ramiz Asəf oğlu. Müstəqillik yollarında: liderlik missiyası / R. A. Qasımov, Z. H. İsmayıl; elmi red. İ. Hacıyev; AMEA Naxçıvan bölməsi.- Naxçıvan: Əcəmi NPB, 2016.- 216 s.
9. Azərbaycan Milli Ensiklopediyası. Azərbaycan. Bakı:” Azərbaycan Millin Ensiklopediyası” Elmi Mərkəzi, 2007, 882 səh.
10. Azərbaycan Respublikası 1991-2001. Bakı: XXI-YNE, 2001, 280 səh.
11. Müstəqillik yollarında. Məqalələr toplusu. Bakı: Şərq-Qərb, 2016, 628 səh.
12. Qocayev Əkbər. Bayramlar və tarixi günlər. Bakı, 2006, 152 səh.