英文諺語中，我們時常說要 dream big，意思不是叫人發個大夢，而是叫人把目光放遠、目標提高，類似中文的「要有大志」。這個夢想不同 day dreaming，一個時常 day dream 的人，就是經常浪費時間，做事不專心，效率極低的人。Day dreaming 和作白日夢的意思不同，前者虛渡光陰，彷彿開著眼睛睡覺；後者妄想多多，不踏實。
西方歷史中，最有名的夢非馬丁路德金 Martin Luther King, Jr. 的人權平等夢想莫屬，因為 MLK 的生辰是美國學校假期，這裡的孩子從小便得老師講解 MLK 的故事，學習他的演說 “I Have A Dream” (我有一個夢)。當然，小孩只當故事聽，大點才明白背後的歷史。
在 1950 年代，美國的非裔、西裔和亞裔移民，受盡歧視。作為一位黑人傳教士，MLK 是帶領群眾，成為史上重要的人權領袖，亦被頒授諾貝爾和平獎。1963年8月28日，他在首都華盛頓的 “I Have A Dream” 演說，促成了於翌年成立的民權法案 Civil Rights Act。
以下是 “I Have A Dream” 演說的部份內容：
I say to you today, my friends, so even though we face the difficulties of today and tomorrow, I still have a dream. It is a dream deeply rooted in the American dream.
I have a dream that one day this nation will rise up and live out the true meaning of its creed: “We hold these truths to be self-evident: that all men are created equal.”
I have a dream that one day on the red hills of Georgia the sons of former slaves and the sons of former slave owners will be able to sit down together at the table of brotherhood.
I have a dream that one day even the state of Mississippi, a state sweltering with the heat of injustice, sweltering with the heat of oppression, will be transformed into an oasis of freedom and justice.
I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character.
I have a dream today.
I have a dream that one day, down in Alabama, with its vicious racists, with its governor having his lips dripping with the words of interposition and nullification; one day right there in Alabama, little black boys and black girls will be able to join hands with little white boys and white girls as sisters and brothers.
I have a dream today.
I have a dream that one day every valley shall be exalted, every hill and mountain shall be made low, the rough places will be made plain, and the crooked places will be made straight, and the glory of the Lord shall be revealed, and all flesh shall see it together.
This is our hope. This is the faith that I go back to the South with. With this faith we will be able to hew out of the mountain of despair a stone of hope. With this faith we will be able to transform the jangling discords of our nation into a beautiful symphony of brotherhood. With this faith we will be able to work together, to pray together, to struggle together, to go to jail together, to stand up for freedom together, knowing that we will be free one day.
MLK 的夢想 (dream) 是人人平等，黑人與白人平起平坐，孩子無分膚色地手牽手一起玩耍，人們不因為膚色而被歧視。這是他的希望 (hope)，他的信念 (faith)。他相信每個人天生是平等的 (All men are created equal)，這是美國夢 (American dream) 的一部分﹐人人都有相同的機會，包括學習、工作、創業等。
MLK 的願望 (wish) 在當時不被看好，但經過一群熱心人士的推動和政客的支持，多年來立下多項法例去保障平等機會 (equal opporutnities) ，教育國民尊重不同的膚色、族裔、宗教、年齡、性別、性傾向和殘障人士，明白 diversity 對社會的重要。有誰會想到四十多年後，美國會出現一位黑人總統奧巴馬 Obama Barack。MLK 的夢想成真了 (Dreams come true)。