Making waterfalls

SELECT * FROM gallery2 WHERE topic_id="990840" UNION SELECT * FROM gallery2 WHERE topic_id="1053819" UNION SELECT * FROM gallery2 WHERE topic_id="1248740" UNION SELECT * FROM gallery2 WHERE topic_id="1175073" UNION SELECT * FROM gallery2 WHERE topic_id="639379" UNION SELECT * FROM gallery2 WHERE topic_id="1323188" UNION SELECT * FROM gallery2 WHERE topic_id="1790344" UNION SELECT * FROM gallery2 WHERE topic_id="259322" UNION SELECT * FROM gallery2 WHERE topic_id="140935" UNION SELECT * FROM gallery2 WHERE topic_id="793586" UNION SELECT * FROM gallery2 WHERE topic_id="984747" UNION SELECT * FROM gallery2 WHERE topic_id="1670170" UNION SELECT * FROM gallery2 WHERE topic_id="426918" UNION SELECT * FROM gallery2 WHERE topic_id="89846" UNION SELECT * FROM gallery2 WHERE topic_id="1281046" UNION SELECT * FROM gallery2 WHERE topic_id="559062"