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ST. LOUIS – The Gateway Arch is one of the most iconic landmarks of St. Louis and the Midwest. At the end of the month, it will be celebrated in the form of a social media challenge.

June 30 (shortened as 6/30) marks an informal celebration of the Gateway Arch known as #Arch630Day. The hashtag corresponds with the height of the Arch, which stands at 630 feet tall. More than half a century since it opened, the Gateway Arch remains the tallest human-made monument in the United States and the largest Arch in the world.

Right now, the Gateway Arch is encouraging St. Louisans to get involved with the hashtag #Arch630Day before the end of the month. Businesses and residents are being asked to participate in the Arch stacking challenge on social media.

As part of the challenge, leaders are asked to measure an iconic item of their choice and calculate how many of those it would take to reach the height of the Gateway Arch. For some prominent organizations, the Arch would amount to 214.4 Stanley Cups or 6,000 stacked ribs.

Participants are asked to share their findings via social media and use the hashtag #Arch630Day. You can tag the Gateway Arch on Facebook, Twitter and Instagram when posting for the social media challenge. For the latest updates from the Gateway Arch, click here.